diff --git a/src/zibot/core/db.py b/src/zibot/core/db.py
index bc104bf..441a43b 100644
--- a/src/zibot/core/db.py
+++ b/src/zibot/core/db.py
@@ -168,3 +168,4 @@ class Highlight(ContainsGuildId, Model):
 
     class Meta:
         table = "highlight"
+        unique_together = (("text", "ownerId"),)