diff --git a/third_party/vaca/include/Vaca/Enum.h b/third_party/vaca/include/Vaca/Enum.h
index 7691483b0..8c01674d4 100644
--- a/third_party/vaca/include/Vaca/Enum.h
+++ b/third_party/vaca/include/Vaca/Enum.h
@@ -34,6 +34,10 @@
 
 namespace Vaca {
 
+#ifdef _MSC_VER
+  #pragma warning(disable: 4251)
+#endif
+
 /**
    This class is used to define enumerations "a la" C++0x.