diff --git a/src/wayland/autotests/client/test_error.cpp b/src/wayland/autotests/client/test_error.cpp
index e57c2efa1c..a4f82cbf15 100644
--- a/src/wayland/autotests/client/test_error.cpp
+++ b/src/wayland/autotests/client/test_error.cpp
@@ -42,6 +42,8 @@ private Q_SLOTS:
     void cleanup();
 
     void testMultipleShellSurfacesForSurface();
+    void testTransientForSameSurface_data();
+    void testTransientForSameSurface();
 
 private:
     Display *m_display = nullptr;
@@ -143,5 +145,27 @@ void ErrorTest::testMultipleShellSurfacesForSurface()
     QCOMPARE(m_connection->errorCode(), EPROTO);
 }
 
+void ErrorTest::testTransientForSameSurface_data()
+{
+    QTest::addColumn<ShellSurface::TransientFlag>("flag");
+
+    QTest::newRow("transient") << ShellSurface::TransientFlag::Default;
+    QTest::newRow("transient no focus") << ShellSurface::TransientFlag::NoFocus;
+}
+
+void ErrorTest::testTransientForSameSurface()
+{
+    // this test verifies that creating a transient shell surface for itself triggers a protocol error
+    QSignalSpy errorSpy(m_connection, &ConnectionThread::errorOccurred);
+    QVERIFY(errorSpy.isValid());
+    QScopedPointer<Surface> surface(m_compositor->createSurface());
+    QScopedPointer<ShellSurface> shellSurface(m_shell->createSurface(surface.data()));
+    QFETCH(ShellSurface::TransientFlag, flag);
+    shellSurface->setTransient(surface.data(), QPoint(), flag);
+    QVERIFY(errorSpy.wait());
+    QVERIFY(m_connection->hasError());
+    QCOMPARE(m_connection->errorCode(), EPROTO);
+}
+
 QTEST_GUILESS_MAIN(ErrorTest)
 #include "test_error.moc"
diff --git a/src/wayland/server/shell_interface.cpp b/src/wayland/server/shell_interface.cpp
index 07725eb50e..37f88f3488 100644
--- a/src/wayland/server/shell_interface.cpp
+++ b/src/wayland/server/shell_interface.cpp
@@ -147,7 +147,7 @@ void ShellInterface::Private::createSurface(wl_client *client, uint32_t version,
         }
     );
     if (it != surfaces.constEnd()) {
-        wl_resource_post_error(surface->resource(), WL_DISPLAY_ERROR_INVALID_OBJECT, "ShellSurface already created");
+        wl_resource_post_error(surface->resource(), WL_SHELL_ERROR_ROLE, "ShellSurface already created");
         return;
     }
     ShellSurfaceInterface *shellSurface = new ShellSurfaceInterface(q, surface, parentResource);
@@ -312,7 +312,12 @@ void ShellSurfaceInterface::Private::setTransientCallback(wl_client *client, wl_
     Q_UNUSED(flags)
     auto s = cast<Private>(resource);
     Q_ASSERT(client == *s->client);
-    s->transientFor = QPointer<SurfaceInterface>(SurfaceInterface::get(parent));
+    auto surface = SurfaceInterface::get(parent);
+    if (surface && s->surface == surface) {
+        wl_resource_post_error(surface->resource(), WL_SHELL_ERROR_ROLE, "Cannot be a transient to itself");
+        return;
+    }
+    s->transientFor = QPointer<SurfaceInterface>(surface);
     s->transientOffset = QPoint(x, y);
     emit s->q_func()->transientChanged(!s->transientFor.isNull());
     emit s->q_func()->transientOffsetChanged(s->transientOffset);