diff --git a/src/_cffi_src/openssl/callbacks.py b/src/_cffi_src/openssl/callbacks.py
index cf2b2da..e215ed4 100644
--- a/src/_cffi_src/openssl/callbacks.py
+++ b/src/_cffi_src/openssl/callbacks.py
@@ -11,7 +11,10 @@
 #include <openssl/crypto.h>
 
 #ifdef _WIN32
+#define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
+#include <Wincrypt.h>
+#include <Winsock2.h>
 #else
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/src/_cffi_src/openssl/cryptography.py b/src/_cffi_src/openssl/cryptography.py
index 9095e3a..4f9378d 100644
--- a/src/_cffi_src/openssl/cryptography.py
+++ b/src/_cffi_src/openssl/cryptography.py
@@ -22,7 +22,10 @@
 #include <openssl/e_os2.h>
 #endif
 #if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
 #include <windows.h>
+#include <Wincrypt.h>
+#include <Winsock2.h>
 #endif
 
 #define CRYPTOGRAPHY_OPENSSL_102_OR_GREATER \