diff --git a/nixos/modules/services/networking/firewall.nix b/nixos/modules/services/networking/firewall.nix
index 0242a3780ffc..27119dcc57c5 100644
--- a/nixos/modules/services/networking/firewall.nix
+++ b/nixos/modules/services/networking/firewall.nix
@@ -325,7 +325,7 @@ in
         example = literalExpression "pkgs.iptables-legacy";
         description =
           lib.mdDoc ''
-            The iptables package to use for running the firewall service."
+            The iptables package to use for running the firewall service.
           '';
       };