diff --git a/system/services/calibre.nix b/system/services/calibre.nix
index c1bfd5c..57ba444 100644
--- a/system/services/calibre.nix
+++ b/system/services/calibre.nix
@@ -28,7 +28,8 @@ in {
     };
   };
   config.services.calibre-web = mkIf cfg.enable {
-    inherit (cfg) enable user group dataDir;
+    inherit (cfg) enable user dataDir;
+    group = mkIf cfg.group cfg.group;
     options = {
       calibreLibrary = cfg.library;
       enableBookConversion = true;