diff --git a/builtin/worktree.c b/builtin/worktree.c
index 214de50d4c..e5b7d6f5ec 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -768,7 +768,7 @@ static char *dwim_branch(const char *path, char **new_branch)
 	int n;
 	int branch_exists;
 	const char *s = worktree_basename(path, &n);
-	char *branchname = xstrndup(s, n);
+	char *branchname = xmemdupz(s, path + n - s);
 	struct strbuf ref = STRBUF_INIT;
 
 	branch_exists = !check_branch_ref(&ref, branchname) &&
@@ -877,7 +877,7 @@ static int add(int ac, const char **av, const char *prefix,
 	if (opts.orphan && !new_branch) {
 		int n;
 		const char *s = worktree_basename(path, &n);
-		new_branch = new_branch_to_free = xstrndup(s, n);
+		new_branch = new_branch_to_free = xmemdupz(s, path + n - s);
 	} else if (opts.orphan) {
 		; /* no-op */
 	} else if (opts.detach) {
diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
index 4ffdd56fb4..9542a17cf3 100755
--- a/t/t2400-worktree-add.sh
+++ b/t/t2400-worktree-add.sh
@@ -298,6 +298,11 @@ test_expect_success '"add" with <branch> omitted' '
 	test_cmp_rev HEAD bat
 '
 
+test_expect_success '"add" with trailing slash and <branch> omitted' '
+	git worktree add waffle/bit/ &&
+	test_cmp_rev HEAD bit
+'
+
 test_expect_success '"add" checks out existing branch of dwimd name' '
 	git branch dwim HEAD~1 &&
 	git worktree add dwim &&
@@ -388,6 +393,14 @@ test_expect_success '"add --orphan (no -b)"' '
 	test_cmp expected actual
 '
 
+test_expect_success '"add --orphan with trailing slash (no -b)"' '
+	test_when_finished "git worktree remove -f -f neworphan" &&
+	git worktree add --orphan ./neworphan/ &&
+	echo refs/heads/neworphan >expected &&
+	git -C neworphan symbolic-ref HEAD >actual &&
+	test_cmp expected actual
+'
+
 test_expect_success '"add --orphan --quiet"' '
 	test_when_finished "git worktree remove -f -f orphandir" &&
 	git worktree add --quiet --orphan -b neworphan orphandir 2>log.actual &&