diff --git a/github/github-accessors.go b/github/github-accessors.go
index ccefd992380..1811a37dd21 100644
--- a/github/github-accessors.go
+++ b/github/github-accessors.go
@@ -718,6 +718,14 @@ func (a *AddProjectV2FieldRequest) GetSingleSelectOptions() []*ProjectV2FieldSin
 	return a.SingleSelectOptions
 }
 
+// GetPullRequests returns the PullRequests slice if it's non-nil, nil otherwise.
+func (a *AddPullRequestsToStackRequest) GetPullRequests() []int {
+	if a == nil || a.PullRequests == nil {
+		return nil
+	}
+	return a.PullRequests
+}
+
 // GetMessage returns the Message field if it's non-nil, zero value otherwise.
 func (a *AddResourcesToCostCenterResponse) GetMessage() string {
 	if a == nil || a.Message == nil {
@@ -11670,6 +11678,14 @@ func (c *CreatePullRequest) GetTitle() string {
 	return *c.Title
 }
 
+// GetPullRequests returns the PullRequests slice if it's non-nil, nil otherwise.
+func (c *CreatePullRequestStackRequest) GetPullRequests() []int {
+	if c == nil || c.PullRequests == nil {
+		return nil
+	}
+	return c.PullRequests
+}
+
 // GetRef returns the Ref field.
 func (c *CreateRef) GetRef() string {
 	if c == nil {
@@ -31438,6 +31454,14 @@ func (p *PullRequestListOptions) GetState() string {
 	return p.State
 }
 
+// GetPullRequest returns the PullRequest field.
+func (p *PullRequestListStacksOptions) GetPullRequest() int {
+	if p == nil {
+		return 0
+	}
+	return p.PullRequest
+}
+
 // GetMerged returns the Merged field if it's non-nil, zero value otherwise.
 func (p *PullRequestMergeResult) GetMerged() bool {
 	if p == nil || p.Merged == nil {
@@ -32054,6 +32078,342 @@ func (p *PullRequestStackBase) GetSHA() string {
 	return p.SHA
 }
 
+// GetRef returns the Ref field.
+func (p *PullRequestStackBranch) GetRef() string {
+	if p == nil {
+		return ""
+	}
+	return p.Ref
+}
+
+// GetRepo returns the Repo field.
+func (p *PullRequestStackBranch) GetRepo() *PullRequestStackRepository {
+	if p == nil {
+		return nil
+	}
+	return p.Repo
+}
+
+// GetSHA returns the SHA field.
+func (p *PullRequestStackBranch) GetSHA() string {
+	if p == nil {
+		return ""
+	}
+	return p.SHA
+}
+
+// GetBase returns the Base field.
+func (p *PullRequestStackDetails) GetBase() *PullRequestStackRef {
+	if p == nil {
+		return nil
+	}
+	return p.Base
+}
+
+// GetCreatedAt returns the CreatedAt field.
+func (p *PullRequestStackDetails) GetCreatedAt() Timestamp {
+	if p == nil {
+		return Timestamp{}
+	}
+	return p.CreatedAt
+}
+
+// GetID returns the ID field.
+func (p *PullRequestStackDetails) GetID() int64 {
+	if p == nil {
+		return 0
+	}
+	return p.ID
+}
+
+// GetNodeID returns the NodeID field.
+func (p *PullRequestStackDetails) GetNodeID() string {
+	if p == nil {
+		return ""
+	}
+	return p.NodeID
+}
+
+// GetNumber returns the Number field.
+func (p *PullRequestStackDetails) GetNumber() int {
+	if p == nil {
+		return 0
+	}
+	return p.Number
+}
+
+// GetOpen returns the Open field.
+func (p *PullRequestStackDetails) GetOpen() bool {
+	if p == nil {
+		return false
+	}
+	return p.Open
+}
+
+// GetPullRequests returns the PullRequests slice if it's non-nil, nil otherwise.
+func (p *PullRequestStackDetails) GetPullRequests() []*PullRequestStackEntry {
+	if p == nil || p.PullRequests == nil {
+		return nil
+	}
+	return p.PullRequests
+}
+
+// GetURL returns the URL field.
+func (p *PullRequestStackDetails) GetURL() string {
+	if p == nil {
+		return ""
+	}
+	return p.URL
+}
+
+// GetBase returns the Base field.
+func (p *PullRequestStackEntry) GetBase() *PullRequestStackBranch {
+	if p == nil {
+		return nil
+	}
+	return p.Base
+}
+
+// GetDraft returns the Draft field.
+func (p *PullRequestStackEntry) GetDraft() bool {
+	if p == nil {
+		return false
+	}
+	return p.Draft
+}
+
+// GetHead returns the Head field.
+func (p *PullRequestStackEntry) GetHead() *PullRequestStackBranch {
+	if p == nil {
+		return nil
+	}
+	return p.Head
+}
+
+// GetHTMLURL returns the HTMLURL field.
+func (p *PullRequestStackEntry) GetHTMLURL() string {
+	if p == nil {
+		return ""
+	}
+	return p.HTMLURL
+}
+
+// GetID returns the ID field.
+func (p *PullRequestStackEntry) GetID() int64 {
+	if p == nil {
+		return 0
+	}
+	return p.ID
+}
+
+// GetMergedAt returns the MergedAt field if it's non-nil, zero value otherwise.
+func (p *PullRequestStackEntry) GetMergedAt() Timestamp {
+	if p == nil || p.MergedAt == nil {
+		return Timestamp{}
+	}
+	return *p.MergedAt
+}
+
+// GetNodeID returns the NodeID field.
+func (p *PullRequestStackEntry) GetNodeID() string {
+	if p == nil {
+		return ""
+	}
+	return p.NodeID
+}
+
+// GetNumber returns the Number field.
+func (p *PullRequestStackEntry) GetNumber() int {
+	if p == nil {
+		return 0
+	}
+	return p.Number
+}
+
+// GetState returns the State field.
+func (p *PullRequestStackEntry) GetState() string {
+	if p == nil {
+		return ""
+	}
+	return p.State
+}
+
+// GetTitle returns the Title field.
+func (p *PullRequestStackEntry) GetTitle() string {
+	if p == nil {
+		return ""
+	}
+	return p.Title
+}
+
+// GetURL returns the URL field.
+func (p *PullRequestStackEntry) GetURL() string {
+	if p == nil {
+		return ""
+	}
+	return p.URL
+}
+
+// GetUser returns the User field.
+func (p *PullRequestStackEntry) GetUser() *User {
+	if p == nil {
+		return nil
+	}
+	return p.User
+}
+
+// GetBase returns the Base field.
+func (p *PullRequestStackMinimal) GetBase() *PullRequestStackRef {
+	if p == nil {
+		return nil
+	}
+	return p.Base
+}
+
+// GetCreatedAt returns the CreatedAt field.
+func (p *PullRequestStackMinimal) GetCreatedAt() Timestamp {
+	if p == nil {
+		return Timestamp{}
+	}
+	return p.CreatedAt
+}
+
+// GetID returns the ID field.
+func (p *PullRequestStackMinimal) GetID() int64 {
+	if p == nil {
+		return 0
+	}
+	return p.ID
+}
+
+// GetNodeID returns the NodeID field.
+func (p *PullRequestStackMinimal) GetNodeID() string {
+	if p == nil {
+		return ""
+	}
+	return p.NodeID
+}
+
+// GetNumber returns the Number field.
+func (p *PullRequestStackMinimal) GetNumber() int {
+	if p == nil {
+		return 0
+	}
+	return p.Number
+}
+
+// GetOpen returns the Open field.
+func (p *PullRequestStackMinimal) GetOpen() bool {
+	if p == nil {
+		return false
+	}
+	return p.Open
+}
+
+// GetPullRequests returns the PullRequests slice if it's non-nil, nil otherwise.
+func (p *PullRequestStackMinimal) GetPullRequests() []*PullRequestStackMinimalEntry {
+	if p == nil || p.PullRequests == nil {
+		return nil
+	}
+	return p.PullRequests
+}
+
+// GetURL returns the URL field.
+func (p *PullRequestStackMinimal) GetURL() string {
+	if p == nil {
+		return ""
+	}
+	return p.URL
+}
+
+// GetDraft returns the Draft field.
+func (p *PullRequestStackMinimalEntry) GetDraft() bool {
+	if p == nil {
+		return false
+	}
+	return p.Draft
+}
+
+// GetHead returns the Head field.
+func (p *PullRequestStackMinimalEntry) GetHead() *PullRequestStackMinimalHead {
+	if p == nil {
+		return nil
+	}
+	return p.Head
+}
+
+// GetMergedAt returns the MergedAt field if it's non-nil, zero value otherwise.
+func (p *PullRequestStackMinimalEntry) GetMergedAt() Timestamp {
+	if p == nil || p.MergedAt == nil {
+		return Timestamp{}
+	}
+	return *p.MergedAt
+}
+
+// GetNumber returns the Number field.
+func (p *PullRequestStackMinimalEntry) GetNumber() int {
+	if p == nil {
+		return 0
+	}
+	return p.Number
+}
+
+// GetState returns the State field.
+func (p *PullRequestStackMinimalEntry) GetState() string {
+	if p == nil {
+		return ""
+	}
+	return p.State
+}
+
+// GetRef returns the Ref field.
+func (p *PullRequestStackMinimalHead) GetRef() string {
+	if p == nil {
+		return ""
+	}
+	return p.Ref
+}
+
+// GetSHA returns the SHA field.
+func (p *PullRequestStackMinimalHead) GetSHA() string {
+	if p == nil {
+		return ""
+	}
+	return p.SHA
+}
+
+// GetRef returns the Ref field.
+func (p *PullRequestStackRef) GetRef() string {
+	if p == nil {
+		return ""
+	}
+	return p.Ref
+}
+
+// GetID returns the ID field.
+func (p *PullRequestStackRepository) GetID() int64 {
+	if p == nil {
+		return 0
+	}
+	return p.ID
+}
+
+// GetName returns the Name field.
+func (p *PullRequestStackRepository) GetName() string {
+	if p == nil {
+		return ""
+	}
+	return p.Name
+}
+
+// GetURL returns the URL field.
+func (p *PullRequestStackRepository) GetURL() string {
+	if p == nil {
+		return ""
+	}
+	return p.URL
+}
+
 // GetBody returns the Body field if it's non-nil, zero value otherwise.
 func (p *PullRequestSubmitReviewRequest) GetBody() string {
 	if p == nil || p.Body == nil {
diff --git a/github/github-accessors_test.go b/github/github-accessors_test.go
index 6ae6420e82b..3ad94da87bc 100644
--- a/github/github-accessors_test.go
+++ b/github/github-accessors_test.go
@@ -908,6 +908,17 @@ func TestAddProjectV2FieldRequest_GetSingleSelectOptions(tt *testing.T) {
 	a.GetSingleSelectOptions()
 }
 
+func TestAddPullRequestsToStackRequest_GetPullRequests(tt *testing.T) {
+	tt.Parallel()
+	zeroValue := []int{}
+	a := &AddPullRequestsToStackRequest{PullRequests: zeroValue}
+	a.GetPullRequests()
+	a = &AddPullRequestsToStackRequest{}
+	a.GetPullRequests()
+	a = nil
+	a.GetPullRequests()
+}
+
 func TestAddResourcesToCostCenterResponse_GetMessage(tt *testing.T) {
 	tt.Parallel()
 	var zeroValue string
@@ -14794,6 +14805,17 @@ func TestCreatePullRequest_GetTitle(tt *testing.T) {
 	c.GetTitle()
 }
 
+func TestCreatePullRequestStackRequest_GetPullRequests(tt *testing.T) {
+	tt.Parallel()
+	zeroValue := []int{}
+	c := &CreatePullRequestStackRequest{PullRequests: zeroValue}
+	c.GetPullRequests()
+	c = &CreatePullRequestStackRequest{}
+	c.GetPullRequests()
+	c = nil
+	c.GetPullRequests()
+}
+
 func TestCreateRef_GetRef(tt *testing.T) {
 	tt.Parallel()
 	c := &CreateRef{}
@@ -39497,6 +39519,14 @@ func TestPullRequestListOptions_GetState(tt *testing.T) {
 	p.GetState()
 }
 
+func TestPullRequestListStacksOptions_GetPullRequest(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestListStacksOptions{}
+	p.GetPullRequest()
+	p = nil
+	p.GetPullRequest()
+}
+
 func TestPullRequestMergeResult_GetMerged(tt *testing.T) {
 	tt.Parallel()
 	var zeroValue bool
@@ -40206,6 +40236,354 @@ func TestPullRequestStackBase_GetSHA(tt *testing.T) {
 	p.GetSHA()
 }
 
+func TestPullRequestStackBranch_GetRef(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackBranch{}
+	p.GetRef()
+	p = nil
+	p.GetRef()
+}
+
+func TestPullRequestStackBranch_GetRepo(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackBranch{}
+	p.GetRepo()
+	p = nil
+	p.GetRepo()
+}
+
+func TestPullRequestStackBranch_GetSHA(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackBranch{}
+	p.GetSHA()
+	p = nil
+	p.GetSHA()
+}
+
+func TestPullRequestStackDetails_GetBase(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetBase()
+	p = nil
+	p.GetBase()
+}
+
+func TestPullRequestStackDetails_GetCreatedAt(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetCreatedAt()
+	p = nil
+	p.GetCreatedAt()
+}
+
+func TestPullRequestStackDetails_GetID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetID()
+	p = nil
+	p.GetID()
+}
+
+func TestPullRequestStackDetails_GetNodeID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetNodeID()
+	p = nil
+	p.GetNodeID()
+}
+
+func TestPullRequestStackDetails_GetNumber(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetNumber()
+	p = nil
+	p.GetNumber()
+}
+
+func TestPullRequestStackDetails_GetOpen(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetOpen()
+	p = nil
+	p.GetOpen()
+}
+
+func TestPullRequestStackDetails_GetPullRequests(tt *testing.T) {
+	tt.Parallel()
+	zeroValue := []*PullRequestStackEntry{}
+	p := &PullRequestStackDetails{PullRequests: zeroValue}
+	p.GetPullRequests()
+	p = &PullRequestStackDetails{}
+	p.GetPullRequests()
+	p = nil
+	p.GetPullRequests()
+}
+
+func TestPullRequestStackDetails_GetURL(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackDetails{}
+	p.GetURL()
+	p = nil
+	p.GetURL()
+}
+
+func TestPullRequestStackEntry_GetBase(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetBase()
+	p = nil
+	p.GetBase()
+}
+
+func TestPullRequestStackEntry_GetDraft(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetDraft()
+	p = nil
+	p.GetDraft()
+}
+
+func TestPullRequestStackEntry_GetHead(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetHead()
+	p = nil
+	p.GetHead()
+}
+
+func TestPullRequestStackEntry_GetHTMLURL(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetHTMLURL()
+	p = nil
+	p.GetHTMLURL()
+}
+
+func TestPullRequestStackEntry_GetID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetID()
+	p = nil
+	p.GetID()
+}
+
+func TestPullRequestStackEntry_GetMergedAt(tt *testing.T) {
+	tt.Parallel()
+	var zeroValue Timestamp
+	p := &PullRequestStackEntry{MergedAt: &zeroValue}
+	p.GetMergedAt()
+	p = &PullRequestStackEntry{}
+	p.GetMergedAt()
+	p = nil
+	p.GetMergedAt()
+}
+
+func TestPullRequestStackEntry_GetNodeID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetNodeID()
+	p = nil
+	p.GetNodeID()
+}
+
+func TestPullRequestStackEntry_GetNumber(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetNumber()
+	p = nil
+	p.GetNumber()
+}
+
+func TestPullRequestStackEntry_GetState(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetState()
+	p = nil
+	p.GetState()
+}
+
+func TestPullRequestStackEntry_GetTitle(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetTitle()
+	p = nil
+	p.GetTitle()
+}
+
+func TestPullRequestStackEntry_GetURL(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetURL()
+	p = nil
+	p.GetURL()
+}
+
+func TestPullRequestStackEntry_GetUser(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackEntry{}
+	p.GetUser()
+	p = nil
+	p.GetUser()
+}
+
+func TestPullRequestStackMinimal_GetBase(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetBase()
+	p = nil
+	p.GetBase()
+}
+
+func TestPullRequestStackMinimal_GetCreatedAt(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetCreatedAt()
+	p = nil
+	p.GetCreatedAt()
+}
+
+func TestPullRequestStackMinimal_GetID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetID()
+	p = nil
+	p.GetID()
+}
+
+func TestPullRequestStackMinimal_GetNodeID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetNodeID()
+	p = nil
+	p.GetNodeID()
+}
+
+func TestPullRequestStackMinimal_GetNumber(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetNumber()
+	p = nil
+	p.GetNumber()
+}
+
+func TestPullRequestStackMinimal_GetOpen(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetOpen()
+	p = nil
+	p.GetOpen()
+}
+
+func TestPullRequestStackMinimal_GetPullRequests(tt *testing.T) {
+	tt.Parallel()
+	zeroValue := []*PullRequestStackMinimalEntry{}
+	p := &PullRequestStackMinimal{PullRequests: zeroValue}
+	p.GetPullRequests()
+	p = &PullRequestStackMinimal{}
+	p.GetPullRequests()
+	p = nil
+	p.GetPullRequests()
+}
+
+func TestPullRequestStackMinimal_GetURL(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimal{}
+	p.GetURL()
+	p = nil
+	p.GetURL()
+}
+
+func TestPullRequestStackMinimalEntry_GetDraft(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalEntry{}
+	p.GetDraft()
+	p = nil
+	p.GetDraft()
+}
+
+func TestPullRequestStackMinimalEntry_GetHead(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalEntry{}
+	p.GetHead()
+	p = nil
+	p.GetHead()
+}
+
+func TestPullRequestStackMinimalEntry_GetMergedAt(tt *testing.T) {
+	tt.Parallel()
+	var zeroValue Timestamp
+	p := &PullRequestStackMinimalEntry{MergedAt: &zeroValue}
+	p.GetMergedAt()
+	p = &PullRequestStackMinimalEntry{}
+	p.GetMergedAt()
+	p = nil
+	p.GetMergedAt()
+}
+
+func TestPullRequestStackMinimalEntry_GetNumber(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalEntry{}
+	p.GetNumber()
+	p = nil
+	p.GetNumber()
+}
+
+func TestPullRequestStackMinimalEntry_GetState(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalEntry{}
+	p.GetState()
+	p = nil
+	p.GetState()
+}
+
+func TestPullRequestStackMinimalHead_GetRef(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalHead{}
+	p.GetRef()
+	p = nil
+	p.GetRef()
+}
+
+func TestPullRequestStackMinimalHead_GetSHA(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackMinimalHead{}
+	p.GetSHA()
+	p = nil
+	p.GetSHA()
+}
+
+func TestPullRequestStackRef_GetRef(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackRef{}
+	p.GetRef()
+	p = nil
+	p.GetRef()
+}
+
+func TestPullRequestStackRepository_GetID(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackRepository{}
+	p.GetID()
+	p = nil
+	p.GetID()
+}
+
+func TestPullRequestStackRepository_GetName(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackRepository{}
+	p.GetName()
+	p = nil
+	p.GetName()
+}
+
+func TestPullRequestStackRepository_GetURL(tt *testing.T) {
+	tt.Parallel()
+	p := &PullRequestStackRepository{}
+	p.GetURL()
+	p = nil
+	p.GetURL()
+}
+
 func TestPullRequestSubmitReviewRequest_GetBody(tt *testing.T) {
 	tt.Parallel()
 	var zeroValue string
diff --git a/github/github-iterators.go b/github/github-iterators.go
index 05120877ca5..fc421373bdd 100644
--- a/github/github-iterators.go
+++ b/github/github-iterators.go
@@ -5355,6 +5355,37 @@ func (s *PullRequestsService) ListReviewsIter(ctx context.Context, owner string,
 	}
 }
 
+// ListStacksIter returns an iterator that paginates through all results of ListStacks.
+func (s *PullRequestsService) ListStacksIter(ctx context.Context, owner string, repo string, opts *PullRequestListStacksOptions) iter.Seq2[*PullRequestStackMinimal, error] {
+	return func(yield func(*PullRequestStackMinimal, error) bool) {
+		// Create a copy of opts to avoid mutating the caller's struct
+		if opts == nil {
+			opts = &PullRequestListStacksOptions{}
+		} else {
+			opts = Ptr(*opts)
+		}
+
+		for {
+			results, resp, err := s.ListStacks(ctx, owner, repo, opts)
+			if err != nil {
+				yield(nil, err)
+				return
+			}
+
+			for _, item := range results {
+				if !yield(item, nil) {
+					return
+				}
+			}
+
+			if resp.NextPage == 0 {
+				break
+			}
+			opts.ListOptions.Page = resp.NextPage
+		}
+	}
+}
+
 // ListCommentReactionsIter returns an iterator that paginates through all results of ListCommentReactions.
 func (s *ReactionsService) ListCommentReactionsIter(ctx context.Context, owner string, repo string, id int64, opts *ListReactionOptions) iter.Seq2[*Reaction, error] {
 	return func(yield func(*Reaction, error) bool) {
diff --git a/github/github-iterators_test.go b/github/github-iterators_test.go
index 75bc9f90c2b..9a85375cb09 100644
--- a/github/github-iterators_test.go
+++ b/github/github-iterators_test.go
@@ -11823,6 +11823,78 @@ func TestPullRequestsService_ListReviewsIter(t *testing.T) {
 	}
 }
 
+func TestPullRequestsService_ListStacksIter(t *testing.T) {
+	t.Parallel()
+	client, mux, _ := setup(t)
+	var callNum int
+	mux.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		callNum++
+		switch callNum {
+		case 1:
+			w.Header().Set("Link", `<https://api.github.com/?page=1>; rel="next"`)
+			fmt.Fprint(w, `[{},{},{}]`)
+		case 2:
+			fmt.Fprint(w, `[{},{},{},{}]`)
+		case 3:
+			fmt.Fprint(w, `[{},{}]`)
+		case 4:
+			w.WriteHeader(http.StatusNotFound)
+		case 5:
+			fmt.Fprint(w, `[{},{}]`)
+		}
+	})
+
+	iter := client.PullRequests.ListStacksIter(t.Context(), "", "", nil)
+	var gotItems int
+	for _, err := range iter {
+		gotItems++
+		if err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+	}
+	if want := 7; gotItems != want {
+		t.Errorf("client.PullRequests.ListStacksIter call 1 got %v items; want %v", gotItems, want)
+	}
+
+	opts := &PullRequestListStacksOptions{}
+	iter = client.PullRequests.ListStacksIter(t.Context(), "", "", opts)
+	gotItems = 0
+	for _, err := range iter {
+		gotItems++
+		if err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+	}
+	if want := 2; gotItems != want {
+		t.Errorf("client.PullRequests.ListStacksIter call 2 got %v items; want %v", gotItems, want)
+	}
+
+	iter = client.PullRequests.ListStacksIter(t.Context(), "", "", nil)
+	gotItems = 0
+	for _, err := range iter {
+		gotItems++
+		if err == nil {
+			t.Error("expected error; got nil")
+		}
+	}
+	if gotItems != 1 {
+		t.Errorf("client.PullRequests.ListStacksIter call 3 got %v items; want 1 (an error)", gotItems)
+	}
+
+	iter = client.PullRequests.ListStacksIter(t.Context(), "", "", nil)
+	gotItems = 0
+	iter(func(item *PullRequestStackMinimal, err error) bool {
+		gotItems++
+		if err != nil {
+			t.Errorf("Unexpected error: %v", err)
+		}
+		return false
+	})
+	if gotItems != 1 {
+		t.Errorf("client.PullRequests.ListStacksIter call 4 got %v items; want 1 (an error)", gotItems)
+	}
+}
+
 func TestReactionsService_ListCommentReactionsIter(t *testing.T) {
 	t.Parallel()
 	client, mux, _ := setup(t)
diff --git a/github/pulls_stacks.go b/github/pulls_stacks.go
new file mode 100644
index 00000000000..39377a711a3
--- /dev/null
+++ b/github/pulls_stacks.go
@@ -0,0 +1,270 @@
+// Copyright 2026 The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package github
+
+import (
+	"context"
+	"fmt"
+)
+
+// PullRequestListStacksOptions specifies the optional parameters to the
+// PullRequestsService.ListStacks method.
+type PullRequestListStacksOptions struct {
+	// PullRequest filters stacks to the stack containing this pull request number.
+	PullRequest int `url:"pull_request,omitempty"`
+
+	ListOptions
+}
+
+// CreatePullRequestStackRequest represents a request to create a pull request stack.
+type CreatePullRequestStackRequest struct {
+	// PullRequests is an ordered list of pull request numbers from the bottom of the stack to the top.
+	PullRequests []int `json:"pull_requests"`
+}
+
+// AddPullRequestsToStackRequest represents a request to append pull requests to a stack.
+type AddPullRequestsToStackRequest struct {
+	// PullRequests is an ordered list of pull request numbers to append from the current top upward.
+	PullRequests []int `json:"pull_requests"`
+}
+
+// PullRequestStackRef represents the branch a pull request stack ultimately
+// targets. The stacked pull request endpoints return the ref alone, unlike
+// PullRequestStackBase, which the pull request endpoints return with a SHA.
+type PullRequestStackRef struct {
+	// Ref is the name of the branch the entire stack ultimately targets.
+	Ref string `json:"ref"`
+}
+
+// PullRequestStackDetails represents a pull request stack returned by
+// PullRequestsService.CreateStack, GetStack, AddToStack, and Unstack.
+type PullRequestStackDetails struct {
+	// ID is the ID of the stack.
+	ID int64 `json:"id"`
+	// Number is the number of the stack.
+	Number int `json:"number"`
+	// NodeID is the global node ID of the stack.
+	NodeID string `json:"node_id"`
+	// URL is the API URL of the stack.
+	URL string `json:"url"`
+	// Base is the branch the entire stack ultimately targets.
+	Base *PullRequestStackRef `json:"base"`
+	// Open reports whether the stack contains any open pull requests.
+	Open bool `json:"open"`
+	// CreatedAt is the time the stack was created.
+	CreatedAt Timestamp `json:"created_at"`
+	// PullRequests contains the pull requests in the stack, from bottom to top.
+	PullRequests []*PullRequestStackEntry `json:"pull_requests"`
+}
+
+// PullRequestStackEntry represents a pull request in a stack returned by
+// PullRequestsService.CreateStack, GetStack, AddToStack, and Unstack.
+type PullRequestStackEntry struct {
+	// ID is the ID of the pull request.
+	ID int64 `json:"id"`
+	// Number is the number of the pull request.
+	Number int `json:"number"`
+	// NodeID is the global node ID of the pull request.
+	NodeID string `json:"node_id"`
+	// URL is the API URL of the pull request.
+	URL string `json:"url"`
+	// HTMLURL is the web URL of the pull request.
+	HTMLURL string `json:"html_url"`
+	// Title is the title of the pull request.
+	Title string `json:"title"`
+	// State is the state of the pull request. Possible values are: "open" and "closed".
+	State string `json:"state"`
+	// Draft reports whether the pull request is a draft.
+	Draft bool `json:"draft"`
+	// MergedAt is the time the pull request was merged, or nil if it is unmerged.
+	MergedAt *Timestamp `json:"merged_at"`
+	// User is the author of the pull request.
+	User *User `json:"user"`
+	// Head is the branch the pull request merges from.
+	Head *PullRequestStackBranch `json:"head"`
+	// Base is the branch the pull request merges into, which is the pull
+	// request below it in the stack.
+	Base *PullRequestStackBranch `json:"base"`
+}
+
+// PullRequestStackBranch represents the head or base branch of a pull request
+// returned by the stacked pull request endpoints.
+type PullRequestStackBranch struct {
+	// Ref is the name of the branch.
+	Ref string `json:"ref"`
+	// SHA is the SHA of the most recent commit on the branch.
+	SHA string `json:"sha"`
+	// Repo is the repository the branch belongs to.
+	Repo *PullRequestStackRepository `json:"repo"`
+}
+
+// PullRequestStackRepository represents the repository a stacked pull
+// request's branch belongs to.
+type PullRequestStackRepository struct {
+	// ID is the ID of the repository.
+	ID int64 `json:"id"`
+	// URL is the API URL of the repository.
+	URL string `json:"url"`
+	// Name is the name of the repository.
+	Name string `json:"name"`
+}
+
+// PullRequestStackMinimal represents a pull request stack returned by
+// PullRequestsService.ListStacks. This endpoint returns less detail about each
+// pull request in the stack than PullRequestStackDetails carries.
+type PullRequestStackMinimal struct {
+	// ID is the ID of the stack.
+	ID int64 `json:"id"`
+	// Number is the number of the stack.
+	Number int `json:"number"`
+	// NodeID is the global node ID of the stack.
+	NodeID string `json:"node_id"`
+	// URL is the API URL of the stack.
+	URL string `json:"url"`
+	// Base is the branch the entire stack ultimately targets.
+	Base *PullRequestStackRef `json:"base"`
+	// Open reports whether the stack contains any open pull requests.
+	Open bool `json:"open"`
+	// CreatedAt is the time the stack was created.
+	CreatedAt Timestamp `json:"created_at"`
+	// PullRequests contains the pull requests in the stack, from bottom to top.
+	PullRequests []*PullRequestStackMinimalEntry `json:"pull_requests"`
+}
+
+// PullRequestStackMinimalEntry represents a pull request in a stack
+// returned by PullRequestsService.ListStacks.
+type PullRequestStackMinimalEntry struct {
+	// Number is the number of the pull request.
+	Number int `json:"number"`
+	// State is the state of the pull request. Possible values are: "open" and "closed".
+	State string `json:"state"`
+	// Draft reports whether the pull request is a draft.
+	Draft bool `json:"draft"`
+	// MergedAt is the time the pull request was merged, or nil if it is unmerged.
+	MergedAt *Timestamp `json:"merged_at"`
+	// Head is the branch the pull request merges from.
+	Head *PullRequestStackMinimalHead `json:"head"`
+}
+
+// PullRequestStackMinimalHead represents the head branch of a pull request
+// returned by PullRequestsService.ListStacks.
+type PullRequestStackMinimalHead struct {
+	// Ref is the name of the branch.
+	Ref string `json:"ref"`
+	// SHA is the SHA of the most recent commit on the branch.
+	SHA string `json:"sha"`
+}
+
+// ListStacks lists pull request stacks in a repository.
+//
+// GitHub API docs: https://docs.github.com/rest/pulls/stacks?apiVersion=2022-11-28#list-pull-request-stacks
+//
+//meta:operation GET /repos/{owner}/{repo}/stacks
+func (s *PullRequestsService) ListStacks(ctx context.Context, owner, repo string, opts *PullRequestListStacksOptions) ([]*PullRequestStackMinimal, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/stacks", owner, repo)
+	u, err := addOptions(u, opts)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	req, err := s.client.NewRequest(ctx, "GET", u, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var stacks []*PullRequestStackMinimal
+	resp, err := s.client.Do(req, &stacks)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return stacks, resp, nil
+}
+
+// CreateStack creates a pull request stack from an ordered list of pull request numbers.
+//
+// GitHub API docs: https://docs.github.com/rest/pulls/stacks?apiVersion=2022-11-28#create-a-pull-request-stack
+//
+//meta:operation POST /repos/{owner}/{repo}/stacks
+func (s *PullRequestsService) CreateStack(ctx context.Context, owner, repo string, body CreatePullRequestStackRequest) (*PullRequestStackDetails, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/stacks", owner, repo)
+	req, err := s.client.NewRequest(ctx, "POST", u, body)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var stack *PullRequestStackDetails
+	resp, err := s.client.Do(req, &stack)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return stack, resp, nil
+}
+
+// GetStack gets a pull request stack by its stack number.
+//
+// GitHub API docs: https://docs.github.com/rest/pulls/stacks?apiVersion=2022-11-28#get-a-pull-request-stack
+//
+//meta:operation GET /repos/{owner}/{repo}/stacks/{stack_number}
+func (s *PullRequestsService) GetStack(ctx context.Context, owner, repo string, stackNumber int) (*PullRequestStackDetails, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/stacks/%v", owner, repo, stackNumber)
+	req, err := s.client.NewRequest(ctx, "GET", u, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var stack *PullRequestStackDetails
+	resp, err := s.client.Do(req, &stack)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return stack, resp, nil
+}
+
+// AddToStack appends pull requests to a pull request stack.
+//
+// GitHub API docs: https://docs.github.com/rest/pulls/stacks?apiVersion=2022-11-28#add-pull-requests-to-a-pull-request-stack
+//
+//meta:operation POST /repos/{owner}/{repo}/stacks/{stack_number}/add
+func (s *PullRequestsService) AddToStack(ctx context.Context, owner, repo string, stackNumber int, body AddPullRequestsToStackRequest) (*PullRequestStackDetails, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/stacks/%v/add", owner, repo, stackNumber)
+	req, err := s.client.NewRequest(ctx, "POST", u, body)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var stack *PullRequestStackDetails
+	resp, err := s.client.Do(req, &stack)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return stack, resp, nil
+}
+
+// Unstack removes the unmerged pull requests from a pull request stack. It
+// returns nil when no pull requests remain and the stack is dissolved.
+//
+// GitHub API docs: https://docs.github.com/rest/pulls/stacks?apiVersion=2022-11-28#remove-pull-requests-from-a-pull-request-stack
+//
+//meta:operation POST /repos/{owner}/{repo}/stacks/{stack_number}/unstack
+func (s *PullRequestsService) Unstack(ctx context.Context, owner, repo string, stackNumber int) (*PullRequestStackDetails, *Response, error) {
+	u := fmt.Sprintf("repos/%v/%v/stacks/%v/unstack", owner, repo, stackNumber)
+	req, err := s.client.NewRequest(ctx, "POST", u, nil)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var stack *PullRequestStackDetails
+	resp, err := s.client.Do(req, &stack)
+	if err != nil {
+		return nil, resp, err
+	}
+
+	return stack, resp, nil
+}
diff --git a/github/pulls_stacks_test.go b/github/pulls_stacks_test.go
new file mode 100644
index 00000000000..42d0c5b959c
--- /dev/null
+++ b/github/pulls_stacks_test.go
@@ -0,0 +1,364 @@
+// Copyright 2026 The go-github AUTHORS. All rights reserved.
+//
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package github
+
+import (
+	"fmt"
+	"net/http"
+	"testing"
+
+	"github.com/google/go-cmp/cmp"
+)
+
+func testPullRequestStackResponse() string {
+	return `{
+		"id":1,
+		"number":42,
+		"node_id":"S_kwDOABCDEF4AAAAA",
+		"url":"https://api.github.com/repos/o/r/stacks/42",
+		"base":{"ref":"main"},
+		"open":true,
+		"created_at":` + referenceTimeStr + `,
+		"pull_requests":[{
+			"id":1001,
+			"number":101,
+			"node_id":"PR_kwDOABCDEF4AAAAA",
+			"url":"https://api.github.com/repos/o/r/pulls/101",
+			"html_url":"https://github.com/o/r/pull/101",
+			"title":"Add a feature",
+			"state":"open",
+			"draft":false,
+			"merged_at":null,
+			"user":{"login":"octocat"},
+			"head":{"ref":"feature","sha":"abc123","repo":{"id":2001,"url":"https://api.github.com/repos/o/r","name":"r"}},
+			"base":{"ref":"main","sha":"def456","repo":{"id":2001,"url":"https://api.github.com/repos/o/r","name":"r"}}
+		}]
+	}`
+}
+
+func testPullRequestStackDetails() *PullRequestStackDetails {
+	repo := &PullRequestStackRepository{
+		ID:   2001,
+		URL:  "https://api.github.com/repos/o/r",
+		Name: "r",
+	}
+
+	return &PullRequestStackDetails{
+		ID:        1,
+		Number:    42,
+		NodeID:    "S_kwDOABCDEF4AAAAA",
+		URL:       "https://api.github.com/repos/o/r/stacks/42",
+		Base:      &PullRequestStackRef{Ref: "main"},
+		Open:      true,
+		CreatedAt: referenceTimestamp,
+		PullRequests: []*PullRequestStackEntry{{
+			ID:      1001,
+			Number:  101,
+			NodeID:  "PR_kwDOABCDEF4AAAAA",
+			URL:     "https://api.github.com/repos/o/r/pulls/101",
+			HTMLURL: "https://github.com/o/r/pull/101",
+			Title:   "Add a feature",
+			State:   "open",
+			Draft:   false,
+			User:    &User{Login: Ptr("octocat")},
+			Head: &PullRequestStackBranch{
+				Ref:  "feature",
+				SHA:  "abc123",
+				Repo: repo,
+			},
+			Base: &PullRequestStackBranch{
+				Ref:  "main",
+				SHA:  "def456",
+				Repo: repo,
+			},
+		}},
+	}
+}
+
+func testPullRequestStackMinimalResponse() string {
+	return `{
+		"id":1,
+		"number":42,
+		"node_id":"S_kwDOABCDEF4AAAAA",
+		"url":"https://api.github.com/repos/o/r/stacks/42",
+		"base":{"ref":"main"},
+		"open":true,
+		"created_at":` + referenceTimeStr + `,
+		"pull_requests":[{
+			"number":101,
+			"state":"open",
+			"draft":false,
+			"merged_at":null,
+			"head":{"ref":"feature","sha":"abc123"}
+		}]
+	}`
+}
+
+func testPullRequestStackMinimal() *PullRequestStackMinimal {
+	return &PullRequestStackMinimal{
+		ID:        1,
+		Number:    42,
+		NodeID:    "S_kwDOABCDEF4AAAAA",
+		URL:       "https://api.github.com/repos/o/r/stacks/42",
+		Base:      &PullRequestStackRef{Ref: "main"},
+		Open:      true,
+		CreatedAt: referenceTimestamp,
+		PullRequests: []*PullRequestStackMinimalEntry{{
+			Number: 101,
+			State:  "open",
+			Draft:  false,
+			Head: &PullRequestStackMinimalHead{
+				Ref: "feature",
+				SHA: "abc123",
+			},
+		}},
+	}
+}
+
+func TestPullRequestsService_ListStacks(t *testing.T) {
+	t.Parallel()
+	client, mux, _ := setup(t)
+
+	mux.HandleFunc("/repos/o/r/stacks", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		testFormValues(t, r, values{
+			"pull_request": "101",
+			"page":         "2",
+			"per_page":     "50",
+		})
+		fmt.Fprintf(w, "[%v]", testPullRequestStackMinimalResponse())
+	})
+
+	opts := &PullRequestListStacksOptions{
+		PullRequest: 101,
+		ListOptions: ListOptions{Page: 2, PerPage: 50},
+	}
+	ctx := t.Context()
+	stacks, _, err := client.PullRequests.ListStacks(ctx, "o", "r", opts)
+	if err != nil {
+		t.Errorf("PullRequests.ListStacks returned error: %v", err)
+	}
+
+	want := []*PullRequestStackMinimal{testPullRequestStackMinimal()}
+	if !cmp.Equal(stacks, want) {
+		t.Errorf("PullRequests.ListStacks returned %+v, want %+v", stacks, want)
+	}
+
+	const methodName = "ListStacks"
+	testBadOptions(t, methodName, func() (err error) {
+		_, _, err = client.PullRequests.ListStacks(ctx, "\n", "\n", opts)
+		return err
+	})
+
+	testNewRequestAndDoFailure(t, methodName, client, func() (*Response, error) {
+		got, resp, err := client.PullRequests.ListStacks(ctx, "o", "r", opts)
+		if got != nil {
+			t.Errorf("testNewRequestAndDoFailure %v = %#v, want nil", methodName, got)
+		}
+		return resp, err
+	})
+}
+
+func TestPullRequestsService_ListStacks_invalidOwner(t *testing.T) {
+	t.Parallel()
+	client, _, _ := setup(t)
+
+	_, _, err := client.PullRequests.ListStacks(t.Context(), "%", "%", nil)
+	testURLParseError(t, err)
+}
+
+func TestPullRequestsService_CreateStack(t *testing.T) {
+	t.Parallel()
+	client, mux, _ := setup(t)
+	input := CreatePullRequestStackRequest{PullRequests: []int{101, 102}}
+
+	mux.HandleFunc("/repos/o/r/stacks", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "POST")
+		testJSONBody(t, r, input)
+		w.WriteHeader(http.StatusCreated)
+		fmt.Fprint(w, testPullRequestStackResponse())
+	})
+
+	ctx := t.Context()
+	stack, _, err := client.PullRequests.CreateStack(ctx, "o", "r", input)
+	if err != nil {
+		t.Errorf("PullRequests.CreateStack returned error: %v", err)
+	}
+	if want := testPullRequestStackDetails(); !cmp.Equal(stack, want) {
+		t.Errorf("PullRequests.CreateStack returned %+v, want %+v", stack, want)
+	}
+
+	const methodName = "CreateStack"
+	testBadOptions(t, methodName, func() (err error) {
+		_, _, err = client.PullRequests.CreateStack(ctx, "\n", "\n", input)
+		return err
+	})
+
+	testNewRequestAndDoFailure(t, methodName, client, func() (*Response, error) {
+		got, resp, err := client.PullRequests.CreateStack(ctx, "o", "r", input)
+		if got != nil {
+			t.Errorf("testNewRequestAndDoFailure %v = %#v, want nil", methodName, got)
+		}
+		return resp, err
+	})
+}
+
+func TestPullRequestsService_CreateStack_invalidOwner(t *testing.T) {
+	t.Parallel()
+	client, _, _ := setup(t)
+
+	_, _, err := client.PullRequests.CreateStack(t.Context(), "%", "%", CreatePullRequestStackRequest{})
+	testURLParseError(t, err)
+}
+
+func TestPullRequestsService_GetStack(t *testing.T) {
+	t.Parallel()
+	client, mux, _ := setup(t)
+
+	mux.HandleFunc("/repos/o/r/stacks/42", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "GET")
+		fmt.Fprint(w, testPullRequestStackResponse())
+	})
+
+	ctx := t.Context()
+	stack, _, err := client.PullRequests.GetStack(ctx, "o", "r", 42)
+	if err != nil {
+		t.Errorf("PullRequests.GetStack returned error: %v", err)
+	}
+	if want := testPullRequestStackDetails(); !cmp.Equal(stack, want) {
+		t.Errorf("PullRequests.GetStack returned %+v, want %+v", stack, want)
+	}
+
+	const methodName = "GetStack"
+	testBadOptions(t, methodName, func() (err error) {
+		_, _, err = client.PullRequests.GetStack(ctx, "\n", "\n", 42)
+		return err
+	})
+
+	testNewRequestAndDoFailure(t, methodName, client, func() (*Response, error) {
+		got, resp, err := client.PullRequests.GetStack(ctx, "o", "r", 42)
+		if got != nil {
+			t.Errorf("testNewRequestAndDoFailure %v = %#v, want nil", methodName, got)
+		}
+		return resp, err
+	})
+}
+
+func TestPullRequestsService_GetStack_invalidOwner(t *testing.T) {
+	t.Parallel()
+	client, _, _ := setup(t)
+
+	_, _, err := client.PullRequests.GetStack(t.Context(), "%", "%", 42)
+	testURLParseError(t, err)
+}
+
+func TestPullRequestsService_AddToStack(t *testing.T) {
+	t.Parallel()
+	client, mux, _ := setup(t)
+	input := AddPullRequestsToStackRequest{PullRequests: []int{103, 104}}
+
+	mux.HandleFunc("/repos/o/r/stacks/42/add", func(w http.ResponseWriter, r *http.Request) {
+		testMethod(t, r, "POST")
+		testJSONBody(t, r, input)
+		fmt.Fprint(w, testPullRequestStackResponse())
+	})
+
+	ctx := t.Context()
+	stack, _, err := client.PullRequests.AddToStack(ctx, "o", "r", 42, input)
+	if err != nil {
+		t.Errorf("PullRequests.AddToStack returned error: %v", err)
+	}
+	if want := testPullRequestStackDetails(); !cmp.Equal(stack, want) {
+		t.Errorf("PullRequests.AddToStack returned %+v, want %+v", stack, want)
+	}
+
+	const methodName = "AddToStack"
+	testBadOptions(t, methodName, func() (err error) {
+		_, _, err = client.PullRequests.AddToStack(ctx, "\n", "\n", 42, input)
+		return err
+	})
+
+	testNewRequestAndDoFailure(t, methodName, client, func() (*Response, error) {
+		got, resp, err := client.PullRequests.AddToStack(ctx, "o", "r", 42, input)
+		if got != nil {
+			t.Errorf("testNewRequestAndDoFailure %v = %#v, want nil", methodName, got)
+		}
+		return resp, err
+	})
+}
+
+func TestPullRequestsService_AddToStack_invalidOwner(t *testing.T) {
+	t.Parallel()
+	client, _, _ := setup(t)
+
+	_, _, err := client.PullRequests.AddToStack(t.Context(), "%", "%", 42, AddPullRequestsToStackRequest{})
+	testURLParseError(t, err)
+}
+
+func TestPullRequestsService_Unstack(t *testing.T) {
+	t.Parallel()
+
+	t.Run("returns updated stack", func(t *testing.T) {
+		t.Parallel()
+		client, mux, _ := setup(t)
+		mux.HandleFunc("/repos/o/r/stacks/42/unstack", func(w http.ResponseWriter, r *http.Request) {
+			testMethod(t, r, "POST")
+			fmt.Fprint(w, testPullRequestStackResponse())
+		})
+
+		stack, _, err := client.PullRequests.Unstack(t.Context(), "o", "r", 42)
+		if err != nil {
+			t.Errorf("PullRequests.Unstack returned error: %v", err)
+		}
+		if want := testPullRequestStackDetails(); !cmp.Equal(stack, want) {
+			t.Errorf("PullRequests.Unstack returned %+v, want %+v", stack, want)
+		}
+	})
+
+	t.Run("returns nil when stack is dissolved", func(t *testing.T) {
+		t.Parallel()
+		client, mux, _ := setup(t)
+		mux.HandleFunc("/repos/o/r/stacks/42/unstack", func(w http.ResponseWriter, r *http.Request) {
+			testMethod(t, r, "POST")
+			w.WriteHeader(http.StatusNoContent)
+		})
+
+		stack, resp, err := client.PullRequests.Unstack(t.Context(), "o", "r", 42)
+		if err != nil {
+			t.Errorf("PullRequests.Unstack returned error: %v", err)
+		}
+		if stack != nil {
+			t.Errorf("PullRequests.Unstack returned %+v, want nil", stack)
+		}
+		if resp.StatusCode != http.StatusNoContent {
+			t.Errorf("PullRequests.Unstack returned status %v, want %v", resp.StatusCode, http.StatusNoContent)
+		}
+	})
+
+	client, _, _ := setup(t)
+	ctx := t.Context()
+	const methodName = "Unstack"
+	testBadOptions(t, methodName, func() (err error) {
+		_, _, err = client.PullRequests.Unstack(ctx, "\n", "\n", 42)
+		return err
+	})
+
+	testNewRequestAndDoFailure(t, methodName, client, func() (*Response, error) {
+		got, resp, err := client.PullRequests.Unstack(ctx, "o", "r", 42)
+		if got != nil {
+			t.Errorf("testNewRequestAndDoFailure %v = %#v, want nil", methodName, got)
+		}
+		return resp, err
+	})
+}
+
+func TestPullRequestsService_Unstack_invalidOwner(t *testing.T) {
+	t.Parallel()
+	client, _, _ := setup(t)
+
+	_, _, err := client.PullRequests.Unstack(t.Context(), "%", "%", 42)
+	testURLParseError(t, err)
+}