diff --git a/nixos/modules/services/networking/ssh/sshd.nix b/nixos/modules/services/networking/ssh/sshd.nix
index a464733a6a03..f900ef494abf 100644
--- a/nixos/modules/services/networking/ssh/sshd.nix
+++ b/nixos/modules/services/networking/ssh/sshd.nix
@@ -263,6 +263,7 @@ in
 
             serviceConfig =
               { ExecStart =
+                  (optionalString cfg.startWhenNeeded "-") +
                   "${cfgc.package}/bin/sshd " + (optionalString cfg.startWhenNeeded "-i ") +
                   "-f ${pkgs.writeText "sshd_config" cfg.extraConfig}";
                 KillMode = "process";