diff --git a/include/internal/catch_common.hpp b/include/internal/catch_common.hpp
index f3e1338a..45785a97 100644
--- a/include/internal/catch_common.hpp
+++ b/include/internal/catch_common.hpp
@@ -24,7 +24,7 @@ namespace Catch {
         return s.find( infix ) != std::string::npos;
     }
     void toLowerInPlace( std::string& s ) {
-        std::transform( s.begin(), s.end(), s.begin(), std::tolower );
+        std::transform( s.begin(), s.end(), s.begin(), static_cast<int(*)(int)>(std::tolower) );
     }
     std::string toLower( std::string const& s ) {
         std::string lc = s;