diff --git a/nixos/modules/system/boot/stage-1.nix b/nixos/modules/system/boot/stage-1.nix
index 86bfde6349c3..1fe1bb14eaf4 100644
--- a/nixos/modules/system/boot/stage-1.nix
+++ b/nixos/modules/system/boot/stage-1.nix
@@ -513,7 +513,12 @@ in
     };
 
     boot.initrd.compressor = mkOption {
-      default = "gzip";
+      default = (
+        if lib.versionAtLeast config.boot.kernelPackages.kernel.version "5.9"
+        then "zstd"
+        else "gzip"
+      );
+      defaultText = "zstd if the kernel supports it (5.9+), gzip if not.";
       type = types.unspecified; # We don't have a function type...
       description = ''
         The compressor to use on the initrd image. May be any of: