diff --git a/modules/ssl/mod_ssl.h b/modules/ssl/mod_ssl.h
index b5974426c6..f96f3c82a8 100644
--- a/modules/ssl/mod_ssl.h
+++ b/modules/ssl/mod_ssl.h
@@ -27,6 +27,7 @@
 #define __MOD_SSL_H__
 
 #include "httpd.h"
+#include "http_config.h"
 #include "apr_optional.h"
 
 /* Create a set of SSL_DECLARE(type), SSL_DECLARE_NONSTD(type) and