diff --git a/nixos/modules/programs/ssh.nix b/nixos/modules/programs/ssh.nix
index db44f9040dde..0f7f0515f0e9 100644
--- a/nixos/modules/programs/ssh.nix
+++ b/nixos/modules/programs/ssh.nix
@@ -211,8 +211,8 @@ in
 
         ForwardX11 ${if cfg.forwardX11 then "yes" else "no"}
 
-        PubkeyAcceptedKeyTypes ${concatStringsSep "," cfg.pubkeyAcceptedKeyTypes}
-        HostKeyAlgorithms ${concatStringsSep "," cfg.hostKeyAlgorithms}
+        ${optionalString (cfg.pubkeyAcceptedKeyTypes != []) PubkeyAcceptedKeyTypes "${concatStringsSep "," cfg.pubkeyAcceptedKeyTypes}"}
+        ${optionalString (cfg.hostKeyAlgorithms != []) HostKeyAlgorithms "${concatStringsSep "," cfg.hostKeyAlgorithms}"}
 
         ${cfg.extraConfig}
       '';