diff --git a/nixos/modules/services/web-servers/apache-httpd/per-server-options.nix b/nixos/modules/services/web-servers/apache-httpd/per-server-options.nix
index 9fb25c37f5b..0db27b0bcbe 100644
--- a/nixos/modules/services/web-servers/apache-httpd/per-server-options.nix
+++ b/nixos/modules/services/web-servers/apache-httpd/per-server-options.nix
@@ -57,7 +57,8 @@ with lib;
   };
 
   sslServerChain = mkOption {
-    type = types.path;
+    type = types.nullOr types.path;
+    default = null;
     example = "/var/ca.pem";
     description = "Path to server SSL chain file.";
   };