diff --git a/builtin/stash.c b/builtin/stash.c
index 49c6d7948a..1bfa24030c 100644
--- a/builtin/stash.c
+++ b/builtin/stash.c
@@ -1515,7 +1515,10 @@ static int use_builtin_stash(void)
 {
 	struct child_process cp = CHILD_PROCESS_INIT;
 	struct strbuf out = STRBUF_INIT;
-	int ret;
+	int ret, env = git_env_bool("GIT_TEST_STASH_USE_BUILTIN", -1);
+
+	if (env != -1)
+		return env;
 
 	argv_array_pushl(&cp.args,
 			 "config", "--bool", "stash.usebuiltin", NULL);
diff --git a/t/README b/t/README
index 28711cc508..9187eeea8e 100644
--- a/t/README
+++ b/t/README
@@ -349,6 +349,10 @@ GIT_TEST_REBASE_USE_BUILTIN=<boolean>, when false, disables the
 builtin version of git-rebase. See 'rebase.useBuiltin' in
 git-config(1).
 
+GIT_TEST_STASH_USE_BUILTIN=<boolean>, when false, disables the
+built-in version of git-stash. See 'stash.useBuiltin' in
+git-config(1).
+
 GIT_TEST_INDEX_THREADS=<n> enables exercising the multi-threaded loading
 of the index for the whole test suite by bypassing the default number of
 cache entries and thread minimums. Setting this to 1 will make the