diff --git a/Include/mappingobject.h b/Include/mappingobject.h
index 8844c77..caedbc7 100644
--- a/Include/mappingobject.h
+++ b/Include/mappingobject.h
@@ -30,7 +30,7 @@
 
 /* Mapping object type -- mapping from hashable object to object */
 
-extern typeobject Mappingtype;
+extern DL_IMPORT typeobject Mappingtype;
 
 #define is_mappingobject(op) ((op)->ob_type == &Mappingtype)