diff --git a/src/nvtt/nvtt.h b/src/nvtt/nvtt.h
index 4b09bca..64f9bc2 100644
--- a/src/nvtt/nvtt.h
+++ b/src/nvtt/nvtt.h
@@ -29,7 +29,7 @@
 // Function linkage
 #if NVTT_SHARED
 
-#if defined _WIN32 || defined WIN32 || defined __NT__ || defined __WIN32__ || defined __MINGW32__
+#if defined _WIN32 || defined WIN32 || defined __NT__ || defined __WIN32__ || defined __MINGW32__  || defined __MINGW64__
 #  ifdef NVTT_EXPORTS
 #    define NVTT_API __declspec(dllexport)
 #  else