diff --git a/src/OpenMesh/Core/IO/Options.hh b/src/OpenMesh/Core/IO/Options.hh
index a459e3e0..05461d43 100644
--- a/src/OpenMesh/Core/IO/Options.hh
+++ b/src/OpenMesh/Core/IO/Options.hh
@@ -51,6 +51,7 @@
 
 // OpenMesh
 #include <OpenMesh/Core/System/config.h>
+#include <string>
 
 
 //== NAMESPACES ==============================================================