diff --git a/nixos/modules/services/networking/syncthing.nix b/nixos/modules/services/networking/syncthing.nix
index 373fd03223d6..5242d3a40350 100644
--- a/nixos/modules/services/networking/syncthing.nix
+++ b/nixos/modules/services/networking/syncthing.nix
@@ -317,11 +317,12 @@ in {
             };
 
             type = mkOption {
-              type = types.enum [ "sendreceive" "sendonly" "receiveonly" ];
+              type = types.enum [ "sendreceive" "sendonly" "receiveonly" "receiveencrypted" ];
               default = "sendreceive";
               description = lib.mdDoc ''
                 Whether to only send changes for this folder, only receive them
-                or both.
+                or both. `receiveencrypted` can be used for untrusted devices. See
+                <https://docs.syncthing.net/users/untrusted.html> for reference.
               '';
             };