diff --git a/guix-build.in b/guix-build.in
index ef9cf3bcc9..cd975e6353 100644
--- a/guix-build.in
+++ b/guix-build.in
@@ -132,7 +132,7 @@ Report bugs to: ~a.~%") "@PACKAGE_BUGREPORT@"))
     ;; Return the alist of option values.
     (args-fold args %options
                (lambda (opt name arg result)
-                 (leave (_ "~A: unrecognized option~%") opt))
+                 (leave (_ "~A: unrecognized option~%") name))
                (lambda (arg result)
                  (alist-cons 'argument arg result))
                %default-options))