diff --git a/nixos/modules/programs/ssh.nix b/nixos/modules/programs/ssh.nix
index 703975fd06c9..80198990ed11 100644
--- a/nixos/modules/programs/ssh.nix
+++ b/nixos/modules/programs/ssh.nix
@@ -251,7 +251,7 @@ in
             ExecStart =
                 "${cfg.package}/bin/ssh-agent " +
                 optionalString (cfg.agentTimeout != null) ("-t ${cfg.agentTimeout} ") +
-                optionalString (cfg.agentPKCS11Whitelist != null) ("-P ${cfg.agentPKCS11Whitelist} ")
+                optionalString (cfg.agentPKCS11Whitelist != null) ("-P ${cfg.agentPKCS11Whitelist} ") +
                 "-a %t/ssh-agent";
             StandardOutput = "null";
             Type = "forking";