diff --git a/AK/TypeCasts.h b/AK/TypeCasts.h
index 6ab8101f32..92e773b208 100644
--- a/AK/TypeCasts.h
+++ b/AK/TypeCasts.h
@@ -26,6 +26,7 @@
 
 #pragma once
 
+#include <AK/Assertions.h>
 #include <AK/Platform.h>
 #include <AK/StdLibExtras.h>