diff --git a/nixos/modules/services/networking/prosody.nix b/nixos/modules/services/networking/prosody.nix
index de316e5f466..40bd9015b1e 100644
--- a/nixos/modules/services/networking/prosody.nix
+++ b/nixos/modules/services/networking/prosody.nix
@@ -422,6 +422,13 @@ in
         description = "List of administrators of the current host";
       };
 
+      authentication = mkOption {
+        type = types.enum [ "internal_plain" "internal_hashed" "cyrus" "anonymous" ];
+        default = "internal_hashed";
+        example = "internal_plain";
+        description = "Authentication mechanism used for logins.";
+      };
+
       extraConfig = mkOption {
         type = types.lines;
         default = "";
@@ -477,6 +484,7 @@ in
 
       s2s_secure_domains = ${toLua cfg.s2sSecureDomains}
 
+      authentication = ${toLua cfg.authentication}
 
       ${ cfg.extraConfig }