diff --git a/Include/asdl.h b/Include/asdl.h
index c1c5603e8ba..d709d42c76d 100644
--- a/Include/asdl.h
+++ b/Include/asdl.h
@@ -5,7 +5,9 @@ typedef PyObject * identifier;
 typedef PyObject * string;
 typedef PyObject * object;
 
+#ifndef __cplusplus
 typedef enum {false, true} bool;
+#endif
 
 /* It would be nice if the code generated by asdl_c.py was completely
    independent of Python, but it is a goal the requires too much work