diff --git a/nixos/modules/services/security/vault.nix b/nixos/modules/services/security/vault.nix
index ab86da47b2e1..650f9bda99c3 100644
--- a/nixos/modules/services/security/vault.nix
+++ b/nixos/modules/services/security/vault.nix
@@ -56,8 +56,8 @@ in
       };
 
       devRootTokenID = mkOption {
-        type = types.str;
-        default = false;
+        type = types.nullOr types.str;
+        default = null;
         description = ''
           Initial root token. This only applies when {option}`services.vault.dev` is true
         '';