diff --git a/Libraries/LibGUI/Event.h b/Libraries/LibGUI/Event.h
index c62d83bc38..c2059558a3 100644
--- a/Libraries/LibGUI/Event.h
+++ b/Libraries/LibGUI/Event.h
@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Vector.h>
 #include <Kernel/KeyCode.h>
 #include <LibCore/Event.h>
 #include <LibGUI/WindowType.h>