diff --git a/amber/src/main/scala/org/apache/texera/web/resource/dashboard/user/workflow/WorkflowResource.scala b/amber/src/main/scala/org/apache/texera/web/resource/dashboard/user/workflow/WorkflowResource.scala
index 6fbd19bcc2c..28d232c867e 100644
--- a/amber/src/main/scala/org/apache/texera/web/resource/dashboard/user/workflow/WorkflowResource.scala
+++ b/amber/src/main/scala/org/apache/texera/web/resource/dashboard/user/workflow/WorkflowResource.scala
@@ -959,6 +959,9 @@ class WorkflowResource extends LazyLogging {
       .where(WORKFLOW.WID.eq(wid))
       .and(WORKFLOW.IS_PUBLIC.isTrue)
       .fetchOne()
+    if (workflow == null) {
+      throw new NotFoundException(s"Public workflow with id $wid not found")
+    }
     // Name and description come from the public copy for the same reason as the content: a pin has
     // to hold everything on show.
     val publicCopy = WorkflowPublishService.publicCopyOf(workflow.into(classOf[Workflow]))
diff --git a/amber/src/test/scala/org/apache/texera/web/resource/dashboard/file/WorkflowResourceSpec.scala b/amber/src/test/scala/org/apache/texera/web/resource/dashboard/file/WorkflowResourceSpec.scala
index 24cbf8da2aa..57616afc72a 100644
--- a/amber/src/test/scala/org/apache/texera/web/resource/dashboard/file/WorkflowResourceSpec.scala
+++ b/amber/src/test/scala/org/apache/texera/web/resource/dashboard/file/WorkflowResourceSpec.scala
@@ -1006,6 +1006,16 @@ class WorkflowResourceSpec
     assertThrows[ForbiddenException](workflowResource.makePublic(wid, sessionUser2))
   }
 
+  "WorkflowResource.retrievePublicWorkflow" should "throw NotFoundException for a private workflow" in {
+    val wid = seedWorkflow(sessionUser1, "public-private-wf").workflow.getWid
+    assertThrows[NotFoundException](workflowResource.retrievePublicWorkflow(wid))
+  }
+
+  it should "throw NotFoundException for a wid that does not exist" in {
+    val wid = seedWorkflow(sessionUser1, "public-missing-wf").workflow.getWid
+    assertThrows[NotFoundException](workflowResource.retrievePublicWorkflow(wid + 100000))
+  }
+
   "WorkflowResource.duplicateWorkflow" should "create a distinct copy owned by the user" in {
     // duplicateWorkflow reassigns operator ids, so the content must have an operators array.
     val wid = seedWorkflow(