diff --git a/src/shapes/ply/ply/ply_parser.hpp b/src/shapes/ply/ply/ply_parser.hpp
index 2229eb74..ac443f45 100644
--- a/src/shapes/ply/ply/ply_parser.hpp
+++ b/src/shapes/ply/ply/ply_parser.hpp
@@ -7,6 +7,7 @@
 #include <sstream>
 #include <string>
 #include <vector>
+#include <cctype>
 
 #if defined(WIN32)
 #include <boost/tr1/functional.hpp>