diff --git a/nixos/modules/services/databases/mongodb.nix b/nixos/modules/services/databases/mongodb.nix
index 129b679d73f8..1eba6fdc60af 100644
--- a/nixos/modules/services/databases/mongodb.nix
+++ b/nixos/modules/services/databases/mongodb.nix
@@ -199,7 +199,7 @@ in
       postStart = ''
         if test -e "${cfg.dbpath}/.first_startup"; then
           ${lib.optionalString (cfg.initialScript != null) ''
-            initialRootPassword=$(<${cfg.initialRootPasswordFile})
+            ${lib.optionalString (cfg.enableAuth) "initialRootPassword=$(<${cfg.initialRootPasswordFile})"}
             ${mongoshExe} ${lib.optionalString (cfg.enableAuth) "-u root -p $initialRootPassword"} admin "${cfg.initialScript}"
           ''}
           rm -f "${cfg.dbpath}/.first_startup"