diff --git a/notes.c b/notes.c
index b7d79e1900..a5d888d772 100644
--- a/notes.c
+++ b/notes.c
@@ -105,6 +105,13 @@ static unsigned char *lookup_notes(const unsigned char *commit_sha1)
 	return hash_map.entries[index].notes_sha1;
 }
 
+void free_notes(void)
+{
+	free(hash_map.entries);
+	memset(&hash_map, 0, sizeof(struct hash_map));
+	initialized = 0;
+}
+
 void get_commit_notes(const struct commit *commit, struct strbuf *sb,
 		const char *output_encoding, int flags)
 {
diff --git a/notes.h b/notes.h
index 7f3eed4384..a1421e351a 100644
--- a/notes.h
+++ b/notes.h
@@ -1,6 +1,9 @@
 #ifndef NOTES_H
 #define NOTES_H
 
+/* Free (and de-initialize) the internal notes tree structure */
+void free_notes(void);
+
 #define NOTES_SHOW_HEADER 1
 #define NOTES_INDENT 2