diff --git a/panda/src/putil/callbackObject.h b/panda/src/putil/callbackObject.h
index 3e1b551eec..c51e1bae0d 100644
--- a/panda/src/putil/callbackObject.h
+++ b/panda/src/putil/callbackObject.h
@@ -16,6 +16,7 @@
 
 #include "pandabase.h"
 #include "typedReferenceCount.h"
+#include "pointerTo.h"
 
 class CallbackData;