diff --git a/dtool/src/parser-inc/windows.h b/dtool/src/parser-inc/windows.h
index 56f0dd9582..2556eef0f8 100644
--- a/dtool/src/parser-inc/windows.h
+++ b/dtool/src/parser-inc/windows.h
@@ -38,4 +38,12 @@ union LARGE_INTEGER {
   __int64 QuadPart;
 };
 
+class IGraphBuilder;
+class ICaptureGraphBuilder2;
+class IBaseFilter;
+class IMediaControl;
+class IVMRWindowlessControl;
+class CSampleGrabberCB;
+template<class N> class CComPtr;
+
 #endif