diff --git a/lib/cpp/src/thrift/protocol/TProtocol.h b/lib/cpp/src/thrift/protocol/TProtocol.h
index 867ceb0..b691c41 100644
--- a/lib/cpp/src/thrift/protocol/TProtocol.h
+++ b/lib/cpp/src/thrift/protocol/TProtocol.h
@@ -22,7 +22,7 @@
 
 #ifdef _WIN32
 // Need to come before any Windows.h includes
-#include <Winsock2.h>
+#include <winsock2.h>
 #endif
 
 #include <thrift/transport/TTransport.h>
diff --git a/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp b/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
index ac24124..d369605 100644
--- a/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
+++ b/lib/cpp/src/thrift/windows/GetTimeOfDay.cpp
@@ -38,7 +38,7 @@
 }
 #else
 #define WIN32_LEAN_AND_MEAN
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <cstdint>
 #include <sstream>
 #include <thrift/transport/TTransportException.h>
diff --git a/lib/cpp/src/thrift/windows/SocketPair.h b/lib/cpp/src/thrift/windows/SocketPair.h
index 86bf431..74b65df 100644
--- a/lib/cpp/src/thrift/windows/SocketPair.h
+++ b/lib/cpp/src/thrift/windows/SocketPair.h
@@ -29,7 +29,7 @@
 #endif
 
 // Win32
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <thrift/thrift-config.h>
 
 int thrift_socketpair(int d, int type, int protocol, THRIFT_SOCKET sv[2]);
diff --git a/lib/cpp/src/thrift/windows/WinFcntl.h b/lib/cpp/src/thrift/windows/WinFcntl.h
index 4816fc5..39e5efd 100644
--- a/lib/cpp/src/thrift/windows/WinFcntl.h
+++ b/lib/cpp/src/thrift/windows/WinFcntl.h
@@ -33,7 +33,7 @@
 #endif
 
 // Win32
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <thrift/transport/PlatformSocket.h>
 
 extern "C" {
diff --git a/lib/cpp/src/thrift/windows/config.h b/lib/cpp/src/thrift/windows/config.h
index ce10c55..19296d6 100644
--- a/lib/cpp/src/thrift/windows/config.h
+++ b/lib/cpp/src/thrift/windows/config.h
@@ -57,7 +57,7 @@
 #include <thrift/windows/SocketPair.h>
 
 // windows
-#include <Winsock2.h>
+#include <winsock2.h>
 #include <ws2tcpip.h>
 
 #ifndef __MINGW32__
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>