diff --git a/app/mainwindow.h b/app/mainwindow.h
--- a/app/mainwindow.h
+++ b/app/mainwindow.h
@@ -123,7 +123,7 @@
 
     void preloadNextUrl();
 
-    void toggleMenuBar();
+    void toggleMenuBar(bool showMessage = true);
     void toggleStatusBar(bool visible);
 
     void showFirstDocumentReached();
diff --git a/app/mainwindow.cpp b/app/mainwindow.cpp
--- a/app/mainwindow.cpp
+++ b/app/mainwindow.cpp
@@ -1523,9 +1523,15 @@
     guiFactory()->refreshActionProperties();
 }
 
-void MainWindow::toggleMenuBar()
+void MainWindow::toggleMenuBar(bool showMessage)
 {
     if (!d->mFullScreenAction->isChecked()) {
+        if (!d->mShowMenuBarAction->isChecked() && showMessage) {
+            const QString accel = d->mShowMenuBarAction->shortcut().toString();
+            KMessageBox::information(this, i18n("This will hide the menu bar completely."
+                                                " You can show it again by typing %1.", accel),
+                                     i18n("Hide menu bar"), QLatin1String("HideMenuBarWarning"));
+        }
         menuBar()->setVisible(d->mShowMenuBarAction->isChecked());
     }
 }