diff --git a/crypto/bio/file.c b/crypto/bio/file.c
index 5d4613178..cef33b666 100644
--- a/crypto/bio/file.c
+++ b/crypto/bio/file.c
@@ -88,7 +88,7 @@
 #define BIO_FP_APPEND 0x08
 
 static FILE *open_file(const char *filename, const char *mode) {
-#if defined(_WIN32) && defined(CP_UTF8)
+#if defined(OPENSSL_WINDOWS) && defined(CP_UTF8)
   int sz, len_0 = (int)strlen(filename) + 1;
   DWORD flags;
 
diff --git a/crypto/err/err.c b/crypto/err/err.c
index 417d3227e..24824e833 100644
--- a/crypto/err/err.c
+++ b/crypto/err/err.c
@@ -633,7 +633,7 @@ void ERR_put_error(int library, int reason, const char *function,
   }
 
   if (library == ERR_LIB_SYS && reason == 0) {
-#if defined(WIN32)
+#if defined(OPENSSL_WINDOWS)
     reason = GetLastError();
 #else
     reason = errno;
diff --git a/include/openssl/base.h b/include/openssl/base.h
index 4618ed202..de14ff474 100644
--- a/include/openssl/base.h
+++ b/include/openssl/base.h
@@ -98,7 +98,7 @@ extern "C" {
 #define OPENSSL_APPLE
 #endif
 
-#if defined(WIN32) || defined(_WIN32)
+#if defined(_WIN32)
 #define OPENSSL_WINDOWS
 #endif