diff --git a/options/locale/locale_en-US.ini b/options/locale/locale_en-US.ini
index fb038cdb76..ae877827c4 100644
--- a/options/locale/locale_en-US.ini
+++ b/options/locale/locale_en-US.ini
@@ -3977,6 +3977,8 @@ workflows.reopen_issue = Reopen issue
 workflows.save_workflow_failed = Failed to save workflow
 workflows.update_workflow_failed = Failed to update workflow status
 workflows.delete_workflow_failed = Failed to delete workflow
+workflows.at_least_one_action_required = At least one action must be configured
+workflows.error.at_least_one_action = At least one action must be configured
 
 [git.filemode]
 changed_filemode = %[1]s → %[2]s
diff --git a/routers/web/projects/workflows.go b/routers/web/projects/workflows.go
index 1897b8434a..0e62bcc3b5 100644
--- a/routers/web/projects/workflows.go
+++ b/routers/web/projects/workflows.go
@@ -442,6 +442,15 @@ func WorkflowsPost(ctx *context.Context) {
 	filters := convertFormToFilters(form.Filters)
 	actions := convertFormToActions(form.Actions)
 
+	// Validate: at least one action must be configured
+	if len(actions) == 0 {
+		ctx.JSON(http.StatusBadRequest, map[string]any{
+			"error":   "NoActions",
+			"message": ctx.Tr("projects.workflows.error.at_least_one_action"),
+		})
+		return
+	}
+
 	eventID, _ := strconv.ParseInt(form.EventID, 10, 64)
 	if eventID == 0 {
 		// check if workflow event is valid
diff --git a/templates/projects/workflows.tmpl b/templates/projects/workflows.tmpl
index 76e17bc229..25ae4db00b 100644
--- a/templates/projects/workflows.tmpl
+++ b/templates/projects/workflows.tmpl
@@ -39,6 +39,7 @@
 		data-locale-save-workflow-failed="{{ctx.Locale.Tr "projects.workflows.save_workflow_failed"}}"
 		data-locale-update-workflow-failed="{{ctx.Locale.Tr "projects.workflows.update_workflow_failed"}}"
 		data-locale-delete-workflow-failed="{{ctx.Locale.Tr "projects.workflows.delete_workflow_failed"}}"
+		data-locale-at-least-one-action-required="{{ctx.Locale.Tr "projects.workflows.at_least_one_action_required"}}"
 	>
 	</div>
 </div>
diff --git a/tests/integration/project_workflow_test.go b/tests/integration/project_workflow_test.go
index 72de6bed08..1e84ce0763 100644
--- a/tests/integration/project_workflow_test.go
+++ b/tests/integration/project_workflow_test.go
@@ -444,3 +444,114 @@ func TestProjectWorkflowPermissions(t *testing.T) {
 		fmt.Sprintf("/%s/%s/projects/%d/workflows/%d/delete?_csrf=%s", user.Name, repo.Name, project.ID, workflow.ID, GetUserCSRFToken(t, session2)))
 	session2.MakeRequest(t, req, http.StatusNotFound) // we use 404 to avoid leaking existence
 }
+
+func TestProjectWorkflowValidation(t *testing.T) {
+	defer tests.PrepareTestEnv(t)()
+
+	user := unittest.AssertExistsAndLoadBean(t, &user_model.User{ID: 2})
+	repo := unittest.AssertExistsAndLoadBean(t, &repo_model.Repository{ID: 1})
+
+	// Create a project
+	project := &project_model.Project{
+		Title:        "Test Project for Workflow Validation",
+		RepoID:       repo.ID,
+		Type:         project_model.TypeRepository,
+		TemplateType: project_model.TemplateTypeNone,
+	}
+	err := project_model.NewProject(t.Context(), project)
+	assert.NoError(t, err)
+
+	session := loginUser(t, user.Name)
+
+	// Test 1: Try to create a workflow without any actions (should fail)
+	t.Run("Create workflow without actions should fail", func(t *testing.T) {
+		workflowData := map[string]any{
+			"event_id": string(project_model.WorkflowEventItemOpened),
+			"filters": map[string]any{
+				string(project_model.WorkflowFilterTypeIssueType): "issue",
+			},
+			"actions": map[string]any{
+				// No actions provided - this should trigger validation error
+			},
+		}
+
+		body, err := json.Marshal(workflowData)
+		assert.NoError(t, err)
+
+		req := NewRequestWithBody(t, "POST",
+			fmt.Sprintf("/%s/%s/projects/%d/workflows/item_opened?_csrf=%s", user.Name, repo.Name, project.ID, GetUserCSRFToken(t, session)),
+			strings.NewReader(string(body)))
+		req.Header.Set("Content-Type", "application/json")
+		resp := session.MakeRequest(t, req, http.StatusBadRequest)
+
+		// Parse response
+		var result map[string]any
+		err = json.Unmarshal(resp.Body.Bytes(), &result)
+		assert.NoError(t, err)
+		assert.Equal(t, "NoActions", result["error"], "Error should be NoActions")
+		assert.NotEmpty(t, result["message"], "Error message should be provided")
+	})
+
+	// Test 2: Try to update a workflow to have no actions (should fail)
+	t.Run("Update workflow to remove all actions should fail", func(t *testing.T) {
+		// First create a valid workflow
+		column := &project_model.Column{
+			Title:     "Test Column",
+			ProjectID: project.ID,
+		}
+		err := project_model.NewColumn(t.Context(), column)
+		assert.NoError(t, err)
+
+		workflow := &project_model.Workflow{
+			ProjectID:     project.ID,
+			WorkflowEvent: project_model.WorkflowEventItemOpened,
+			WorkflowFilters: []project_model.WorkflowFilter{
+				{
+					Type:  project_model.WorkflowFilterTypeIssueType,
+					Value: "issue",
+				},
+			},
+			WorkflowActions: []project_model.WorkflowAction{
+				{
+					Type:  project_model.WorkflowActionTypeColumn,
+					Value: strconv.FormatInt(column.ID, 10),
+				},
+			},
+			Enabled: true,
+		}
+		err = project_model.CreateWorkflow(t.Context(), workflow)
+		assert.NoError(t, err)
+
+		// Try to update it to have no actions
+		updateData := map[string]any{
+			"event_id": strconv.FormatInt(workflow.ID, 10),
+			"filters": map[string]any{
+				string(project_model.WorkflowFilterTypeIssueType): "issue",
+			},
+			"actions": map[string]any{
+				// No actions - should fail
+			},
+		}
+
+		body, err := json.Marshal(updateData)
+		assert.NoError(t, err)
+
+		req := NewRequestWithBody(t, "POST",
+			fmt.Sprintf("/%s/%s/projects/%d/workflows/%d?_csrf=%s", user.Name, repo.Name, project.ID, workflow.ID, GetUserCSRFToken(t, session)),
+			strings.NewReader(string(body)))
+		req.Header.Set("Content-Type", "application/json")
+		resp := session.MakeRequest(t, req, http.StatusBadRequest)
+
+		// Parse response
+		var result map[string]any
+		err = json.Unmarshal(resp.Body.Bytes(), &result)
+		assert.NoError(t, err)
+		assert.Equal(t, "NoActions", result["error"], "Error should be NoActions")
+		assert.NotEmpty(t, result["message"], "Error message should be provided")
+
+		// Verify the workflow was not changed
+		unchangedWorkflow, err := project_model.GetWorkflowByID(t.Context(), workflow.ID)
+		assert.NoError(t, err)
+		assert.Len(t, unchangedWorkflow.WorkflowActions, 1, "Workflow should still have the original action")
+	})
+}
diff --git a/web_src/js/components/projects/ProjectWorkflow.vue b/web_src/js/components/projects/ProjectWorkflow.vue
index d64abc3efe..5341ac9881 100644
--- a/web_src/js/components/projects/ProjectWorkflow.vue
+++ b/web_src/js/components/projects/ProjectWorkflow.vue
@@ -49,6 +49,7 @@ const props = defineProps<{
     saveWorkflowFailed: string;
     updateWorkflowFailed: string;
     deleteWorkflowFailed: string;
+    atLeastOneActionRequired: string;
   },
 }>();
 
diff --git a/web_src/js/components/projects/WorkflowStore.ts b/web_src/js/components/projects/WorkflowStore.ts
index c707b719aa..0e6c485396 100644
--- a/web_src/js/components/projects/WorkflowStore.ts
+++ b/web_src/js/components/projects/WorkflowStore.ts
@@ -176,6 +176,19 @@ export function createWorkflowStore(props: any) {
     async saveWorkflow() {
       if (!store.selectedWorkflow) return;
 
+      // Validate: at least one action must be configured
+      const hasAtLeastOneAction = !!(
+        store.workflowActions.column ||
+        store.workflowActions.add_labels.length > 0 ||
+        store.workflowActions.remove_labels.length > 0 ||
+        store.workflowActions.issue_state
+      );
+
+      if (!hasAtLeastOneAction) {
+        showErrorToast(props.locale.atLeastOneActionRequired || 'At least one action must be configured');
+        return;
+      }
+
       store.saving = true;
       try {
         // For new workflows, use the base event type
@@ -196,9 +209,20 @@ export function createWorkflowStore(props: any) {
         });
 
         if (!response.ok) {
-          const errorText = await response.text();
-          console.error('Response error:', errorText);
-          showErrorToast(`${props.locale.failedToSaveWorkflow}: ${response.status} ${response.statusText}\n${errorText}`);
+          let errorMessage = `${props.locale.failedToSaveWorkflow}: ${response.status} ${response.statusText}`;
+          try {
+            const errorData = await response.json();
+            if (errorData.message) {
+              errorMessage = errorData.message;
+            } else if (errorData.error === 'NoActions') {
+              errorMessage = props.locale.atLeastOneActionRequired || 'At least one action must be configured';
+            }
+          } catch {
+            const errorText = await response.text();
+            console.error('Response error:', errorText);
+            errorMessage += `\n${errorText}`;
+          }
+          showErrorToast(errorMessage);
           return;
         }
 
diff --git a/web_src/js/features/projects/workflow.ts b/web_src/js/features/projects/workflow.ts
index 54f5773c4f..75b98fa9c7 100644
--- a/web_src/js/features/projects/workflow.ts
+++ b/web_src/js/features/projects/workflow.ts
@@ -44,6 +44,7 @@ export async function initProjectWorkflow() {
       saveWorkflowFailed: workflowDiv.getAttribute('data-locale-save-workflow-failed'),
       updateWorkflowFailed: workflowDiv.getAttribute('data-locale-update-workflow-failed'),
       deleteWorkflowFailed: workflowDiv.getAttribute('data-locale-delete-workflow-failed'),
+      atLeastOneActionRequired: workflowDiv.getAttribute('data-locale-at-least-one-action-required'),
     };
 
     const View = createApp(ProjectWorkflow, {