diff --git a/t/test-lib.sh b/t/test-lib.sh
index 05f6e79560..c3d3984b33 100755
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -26,6 +26,7 @@ unset GIT_DIR
 unset GIT_EXTERNAL_DIFF
 unset GIT_INDEX_FILE
 unset GIT_OBJECT_DIRECTORY
+unset GIT_TRACE
 unset SHA1_FILE_DIRECTORIES
 unset SHA1_FILE_DIRECTORY
 export GIT_AUTHOR_EMAIL GIT_AUTHOR_NAME