diff --git a/refs/ref-cache.c b/refs/ref-cache.c
index ffef01a597579e..a3bc2dc11b7ab2 100644
--- a/refs/ref-cache.c
+++ b/refs/ref-cache.c
@@ -506,7 +506,7 @@ static int cache_ref_iterator_seek(struct ref_iterator *ref_iterator,
 			sort_ref_dir(dir);
 
 			slash = strchr(slash, '/');
-			len = slash ? (size_t)(slash - refname) : strlen(refname);
+			len = slash ? (size_t)(slash - refname + 1) : strlen(refname);
 
 			for (idx = 0; idx < dir->nr; idx++) {
 				cmp = strncmp(refname, dir->entries[idx]->name, len);
@@ -520,6 +520,8 @@ static int cache_ref_iterator_seek(struct ref_iterator *ref_iterator,
 				slash = slash + 1;
 
 			level->index = idx;
+			if (cmp > 0)
+				break;
 			if (dir->entries[idx]->flag & REF_DIR) {
 				/* push down a level */
 				dir = get_ref_dir(dir->entries[idx]);
@@ -532,7 +534,7 @@ static int cache_ref_iterator_seek(struct ref_iterator *ref_iterator,
 				level->prefix_state = PREFIX_CONTAINS_DIR;
 			} else {
 				/* reduce the index so the leaf node is iterated over */
-				if (cmp <= 0 && !slash)
+				if (cmp < 0 || (cmp == 0 && !slash))
 					level->index = idx - 1;
 				/*
 				 * while the seek path may not be exhausted, our
diff --git a/t/t6302-for-each-ref-filter.sh b/t/t6302-for-each-ref-filter.sh
index 7f060d97bf509c..826fc1b9f2bfbc 100755
--- a/t/t6302-for-each-ref-filter.sh
+++ b/t/t6302-for-each-ref-filter.sh
@@ -746,6 +746,61 @@ test_expect_success 'start after used with a pattern' '
 	test_cmp expect actual
 '
 
+for storage in loose packed mixed
+do
+	test_expect_success "start after respects directory boundaries ($storage)" '
+		test_when_finished "rm -rf repo" &&
+		git init repo &&
+		(
+			cd repo &&
+			test_commit --no-tag base &&
+			git update-ref refs/tags/packed HEAD &&
+			if test "$storage" = mixed
+			then
+				git pack-refs --all || return 1
+			fi &&
+			git update-ref --stdin <<-\EOF &&
+			create refs/tags/a-leaf HEAD
+			create refs/tags/a/nested HEAD
+			create refs/tags/a0 HEAD
+			create refs/tags/b HEAD
+			create refs/tags/releases-z HEAD
+			create refs/tags/releases/v1 HEAD
+			create refs/tags/releases/v2 HEAD
+			EOF
+			if test "$storage" = packed
+			then
+				git pack-refs --all || return 1
+			fi &&
+			echo refs/tags/releases/v2 >expect &&
+			git for-each-ref --no-sort --format="%(refname)" \
+				--start-after=refs/tags/releases/v1 >actual &&
+			test_cmp expect actual &&
+			cat >expect <<-\EOF &&
+			refs/tags/a0
+			refs/tags/b
+			refs/tags/packed
+			refs/tags/releases-z
+			refs/tags/releases/v1
+			refs/tags/releases/v2
+			EOF
+			git for-each-ref --no-sort --format="%(refname)" \
+				--start-after=refs/tags/a/next >actual &&
+			test_cmp expect actual &&
+			tail -n 5 expect >expect-later &&
+			git for-each-ref --no-sort --format="%(refname)" \
+				--start-after=refs/tags/aa/missing >actual &&
+			test_cmp expect-later actual &&
+			for marker in refs/tags/zzzz refs/zzzz zzzz
+			do
+				git for-each-ref --no-sort --format="%(refname)" \
+					--start-after="$marker" >actual &&
+				test_must_be_empty actual || return 1
+			done
+		)
+	'
+done
+
 test_expect_success 'start after used with custom sort order' '
 	cat >expect <<-\EOF &&
 	fatal: cannot use --start-after with custom sort options