diff --git a/nixos/modules/config/fonts/fontconfig.nix b/nixos/modules/config/fonts/fontconfig.nix
index 861b17cc96a2..16b22841ac14 100644
--- a/nixos/modules/config/fonts/fontconfig.nix
+++ b/nixos/modules/config/fonts/fontconfig.nix
@@ -154,7 +154,7 @@ let
       <fontconfig>
 
         <!-- User defined aliases -->
-        ${lib.concatStringsSep "" (lib.mapAttrsToList mkAliasBlock cfg.aliases)}
+        ${lib.concatStrings (lib.mapAttrsToList mkAliasBlock cfg.aliases)}
 
       </fontconfig>
     '';