diff --git a/vcg/simplex/face/topology.h b/vcg/simplex/face/topology.h
index 52823758..fc0d8cba 100644
--- a/vcg/simplex/face/topology.h
+++ b/vcg/simplex/face/topology.h
@@ -25,6 +25,7 @@
 #define _VCG_FACE_TOPOLOGY
 
 #include <vcg/simplex/face/pos.h>
+#include <set>
 
 namespace vcg {
 namespace face {