diff --git a/modules/system/justfile.nix b/modules/system/justfile.nix
index 57b2bcb..7f72cf4 100644
--- a/modules/system/justfile.nix
+++ b/modules/system/justfile.nix
@@ -58,4 +58,7 @@ in
 {
   # Global Just recipes (system-wide). Used when `XDG_CONFIG_DIRS` includes `/etc/xdg` (default).
   environment.etc."xdg/just/justfile".text = justfileText;
+
+  # Make `just` pick up the global justfile by default (otherwise it only searches CWD/parents).
+  environment.sessionVariables.JUSTFILE = "/etc/xdg/just/justfile";
 }