diff --git a/nixos/modules/services/mail/dovecot.nix b/nixos/modules/services/mail/dovecot.nix
index cdbb776454b6..3fd06812c675 100644
--- a/nixos/modules/services/mail/dovecot.nix
+++ b/nixos/modules/services/mail/dovecot.nix
@@ -181,7 +181,7 @@ in
     };
 
     configFile = mkOption {
-      type = types.nullOr types.str;
+      type = types.nullOr types.path;
       default = null;
       description = "Config file used for the whole dovecot configuration.";
       apply = v: if v != null then v else pkgs.writeText "dovecot.conf" dovecotConf;