diff --git a/pathwaysutils/experimental/gke/jobset.py b/pathwaysutils/experimental/gke/jobset.py
index 8089851..3524733 100644
--- a/pathwaysutils/experimental/gke/jobset.py
+++ b/pathwaysutils/experimental/gke/jobset.py
@@ -859,6 +859,10 @@ def add_user_workload(
   ) -> "PathwaysJobSet":
     """Adds a user workload container to the head pod.
 
+    By default, mounts a memory-backed `emptyDir` (`medium: Memory`) volume
+    named `dshm` at `/dev/shm` unless `volume_mounts` already defines a
+    `/dev/shm` mount.
+
     Args:
       image: Docker image for the user workload.
       command: Command to execute in the container (string or sequence of
@@ -890,6 +894,25 @@ def add_user_workload(
     )
     _apply_container_kwargs(user_container, container_kwargs)
 
+    volume_mounts = list(user_container.volume_mounts or [])
+    if not any(
+        getattr(vm, "mount_path", None) == "/dev/shm"
+        or (isinstance(vm, Mapping) and vm.get("mountPath") == "/dev/shm")
+        for vm in volume_mounts
+    ):
+      shm_volume_name = "dshm"
+      self._add_volume_to_pod_spec(
+          pod_spec,
+          client.V1Volume(
+              name=shm_volume_name,
+              empty_dir=client.V1EmptyDirVolumeSource(medium="Memory"),
+          ),
+      )
+      volume_mounts.append(
+          client.V1VolumeMount(name=shm_volume_name, mount_path="/dev/shm")
+      )
+      user_container.volume_mounts = volume_mounts
+
     init_containers = list(pod_spec.init_containers or [])
     containers = []
     for c in pod_spec.containers:
diff --git a/pathwaysutils/test/experimental/gke/jobset_test.py b/pathwaysutils/test/experimental/gke/jobset_test.py
index 596ee75..2e1c5f8 100644
--- a/pathwaysutils/test/experimental/gke/jobset_test.py
+++ b/pathwaysutils/test/experimental/gke/jobset_test.py
@@ -1130,6 +1130,34 @@ def test_add_user_workload(self):
     self.assertNotIn("pathways-proxy", helper.containers["pathways-head"])
     self.assertIn("user-workload", helper.containers["pathways-head"])
 
+    # Verify memory-backed /dev/shm emptyDir volume and mount on user-workload
+    head_volumes = helper.pod_specs["pathways-head"]["volumes"]
+    self.assertIn(
+        {"name": "dshm", "emptyDir": {"medium": "Memory"}},
+        head_volumes,
+    )
+    self.assertIn(
+        {"name": "dshm", "mountPath": "/dev/shm"},
+        user_c["volumeMounts"],
+    )
+
+  def test_add_user_workload_custom_shm_mount_skips_default_dshm(self):
+    pw_jobset = self._create_jobset(topology="2x2", num_slices=1)
+    pw_jobset.add_user_workload(
+        image="us-docker.pkg.dev/my-project/test:v1",
+        command=["python3", "test.py"],
+        volume_mounts=[
+            client.V1VolumeMount(name="custom-shm", mount_path="/dev/shm")
+        ],
+    )
+    helper = JobSetManifestHelper(pw_jobset.to_dict())
+    self.assertNotIn("dshm", helper.volumes["pathways-head"])
+    user_c = helper.containers["pathways-head"]["user-workload"]
+    self.assertEqual(
+        user_c["volumeMounts"],
+        [{"name": "custom-shm", "mountPath": "/dev/shm"}],
+    )
+
   def test_add_user_workload_roundtrip(self):
     pw_jobset = self._create_jobset(topology="2x2", num_slices=1)
     pw_jobset.add_user_workload(