diff --git a/nixos/modules/services/networking/hostapd.nix b/nixos/modules/services/networking/hostapd.nix
index e9569b2ba6b..f719ff59cc7 100644
--- a/nixos/modules/services/networking/hostapd.nix
+++ b/nixos/modules/services/networking/hostapd.nix
@@ -68,6 +68,7 @@ in
       interface = mkOption {
         default = "";
         example = "wlp2s0";
+        type = types.str;
         description = ''
           The interfaces <command>hostapd</command> will use.
         '';