diff --git a/lib/cpp/test/OpenSSLManualInitTest.cpp b/lib/cpp/test/OpenSSLManualInitTest.cpp
index 935a205..bf6c153 100644
--- a/lib/cpp/test/OpenSSLManualInitTest.cpp
+++ b/lib/cpp/test/OpenSSLManualInitTest.cpp
@@ -21,7 +21,7 @@
 // which will cause the test to fail
 #define MANUAL_OPENSSL_INIT 1
 #ifdef _WIN32
-#include <WinSock2.h>
+#include <winsock2.h>
 #endif
 
 #include <boost/test/unit_test.hpp>