diff --git a/data/model/oci/tag.py b/data/model/oci/tag.py
index 0a7706c96..bba4f766c 100644
--- a/data/model/oci/tag.py
+++ b/data/model/oci/tag.py
@@ -421,7 +421,7 @@ def set_tag_end_ms(tag, end_ms):
                        .where(TagToRepositoryTag.tag == tag)
                        .get()).repository_tag
 
-      old_style_tag.lifetime_end_ts = end_ms / 1000
+      old_style_tag.lifetime_end_ts = end_ms / 1000 if end_ms is not None else None
       old_style_tag.save()
     except TagToRepositoryTag.DoesNotExist:
       pass
diff --git a/data/model/oci/test/test_oci_tag.py b/data/model/oci/test/test_oci_tag.py
index 5e1b6a2bb..c27c182df 100644
--- a/data/model/oci/test/test_oci_tag.py
+++ b/data/model/oci/test/test_oci_tag.py
@@ -214,6 +214,13 @@ def test_change_tag_expiration(timedelta, expected_timedelta, initialized_db):
   expected_ms = (updated_tag.lifetime_start_ms + offset)
   assert updated_tag.lifetime_end_ms == expected_ms
 
+  original_end_ms, okay = change_tag_expiration(tag, None)
+  assert okay
+  assert original_end_ms == expected_ms
+
+  updated_tag = Tag.get(id=tag.id)
+  assert updated_tag.lifetime_end_ms is None
+
 
 def test_set_tag_expiration_for_manifest(initialized_db):
   tag = Tag.get()