diff --git a/abstract_client.cpp b/abstract_client.cpp
--- a/abstract_client.cpp
+++ b/abstract_client.cpp
@@ -274,6 +274,8 @@
     // Since the desktop is also activated, nothing should be in the ActiveLayer, though
     if (isInternal())
         return UnmanagedLayer;
+    if (isLockScreen())
+        return UnmanagedLayer;
     if (isDesktop())
         return workspace()->showingDesktop() ? AboveLayer : DesktopLayer;
     if (isSplash())          // no damn annoying splashscreens
diff --git a/autotests/integration/lockscreen.cpp b/autotests/integration/lockscreen.cpp
--- a/autotests/integration/lockscreen.cpp
+++ b/autotests/integration/lockscreen.cpp
@@ -61,6 +61,7 @@
     void initTestCase();
     void init();
     void cleanup();
+    void testStackingOrder();
     void testPointer();
     void testPointerButton();
     void testPointerAxis();
@@ -221,6 +222,24 @@
     Test::destroyWaylandConnection();
 }
 
+void LockScreenTest::testStackingOrder()
+{
+    // This test verifies that the lockscreen greeter is placed above other windows.
+
+    QSignalSpy clientAddedSpy(waylandServer(), &WaylandServer::shellClientAdded);
+    QVERIFY(clientAddedSpy.isValid());
+
+    LOCK
+    QVERIFY(clientAddedSpy.wait());
+
+    AbstractClient *client = clientAddedSpy.first().first().value<AbstractClient *>();
+    QVERIFY(client);
+    QVERIFY(client->isLockScreen());
+    QCOMPARE(client->layer(), UnmanagedLayer);
+
+    UNLOCK
+}
+
 void LockScreenTest::testPointer()
 {
     using namespace KWayland::Client;