diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -25,6 +25,7 @@ commit id embedding:
 '
 
 . ./test-lib.sh
+TAR=${TAR:-tar}
 
 test_expect_success \
     'populate workdir' \