diff --git a/src/Mod/Part/App/TopoShape.h b/src/Mod/Part/App/TopoShape.h
index 9154de03d1..d7c8902b15 100644
--- a/src/Mod/Part/App/TopoShape.h
+++ b/src/Mod/Part/App/TopoShape.h
@@ -25,6 +25,7 @@
 
 #include <iosfwd>
 #include <list>
+#include <unordered_map>
 
 #include <App/ComplexGeoData.h>
 #include <Base/Exception.h>