diff --git a/pkgs/os-specific/darwin/reattach-to-user-namespace/default.nix b/pkgs/os-specific/darwin/reattach-to-user-namespace/default.nix
index dedc75789510..b4d26327bdcd 100644
--- a/pkgs/os-specific/darwin/reattach-to-user-namespace/default.nix
+++ b/pkgs/os-specific/darwin/reattach-to-user-namespace/default.nix
@@ -11,7 +11,10 @@ stdenv.mkDerivation rec {
     sha256 = "1qgimh58hcx5f646gj2kpd36ayvrdkw616ad8cb3lcm11kg0ag79";
   };
 
-  buildFlags = [ "ARCHES=x86_64" ];
+  buildFlags =
+    if stdenv.hostPlatform.system == "x86_64-darwin" then [ "ARCHES=x86_64" ]
+    else if stdenv.hostPlatform.system == "aarch64-darwin" then [ "ARCHES=arm64" ]
+    else throw "reattach-to-user-namespace isn't being built for ${stdenv.hostPlatform.system} yet.";
 
   installPhase = ''
     mkdir -p $out/bin