diff --git a/nixos/modules/services/x11/xserver.nix b/nixos/modules/services/x11/xserver.nix
index c3cd550e838..70df18b4020 100644
--- a/nixos/modules/services/x11/xserver.nix
+++ b/nixos/modules/services/x11/xserver.nix
@@ -221,7 +221,7 @@ in
 
       dpi = mkOption {
         type = types.nullOr types.int;
-        default = 0;
+        default = null;
         description = "DPI resolution to use for X server.";
       };