diff --git a/ext/openssl/openssl.c b/ext/openssl/openssl.c
index 36efd1b4d21..85731faa02b 100644
--- a/ext/openssl/openssl.c
+++ b/ext/openssl/openssl.c
@@ -35,6 +35,9 @@
 #include "ext/standard/php_fopen_wrappers.h"
 #include "ext/standard/md5.h"
 #include "ext/standard/base64.h"
+#ifdef PHP_WIN32
+# include "win32/winutil.h"
+#endif
 
 /* OpenSSL includes */
 #include <openssl/evp.h>