diff --git a/dtool/src/parser-inc/iostream b/dtool/src/parser-inc/iostream
index 93a736890e..4524e7486d 100644
--- a/dtool/src/parser-inc/iostream
+++ b/dtool/src/parser-inc/iostream
@@ -23,6 +23,7 @@
 #include <ios>
 #include <streambuf>
 #include <ostream>
+#include <Python.h>
 
 // We don't care (much) about the actual definition of the various
 // iostream classes, but we do need to know the classnames that are