diff --git a/panda/src/express/weakPointerToVoid.h b/panda/src/express/weakPointerToVoid.h
index 5ac1049fe3..5b130463e6 100644
--- a/panda/src/express/weakPointerToVoid.h
+++ b/panda/src/express/weakPointerToVoid.h
@@ -17,6 +17,7 @@
 #include "pandabase.h"
 #include "pointerToVoid.h"
 #include "weakPointerCallback.h"
+#include "weakReferenceList.h"
 
 /**
  * This is the specialization of PointerToVoid for weak pointers.  It needs an