diff --git a/models/migrations/migrations.go b/models/migrations/migrations.go
index 1300065ab..d35203093 100644
--- a/models/migrations/migrations.go
+++ b/models/migrations/migrations.go
@@ -186,6 +186,8 @@ var migrations = []Migration{
 	NewMigration("add u2f", addU2FReg),
 	// v66 -> v67
 	NewMigration("add login source id column for public_key table", addLoginSourceIDToPublicKeyTable),
+	// v67 -> v68
+	NewMigration("clean unlinked webhook and hook_task", cleanUnlinkedWebhookAndHookTasks),
 }
 
 // Migrate database to current version
diff --git a/models/migrations/v67.go b/models/migrations/v67.go
new file mode 100644
index 000000000..c7c0914f0
--- /dev/null
+++ b/models/migrations/v67.go
@@ -0,0 +1,13 @@
+// Copyright 2017 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+package migrations
+
+import (
+	"github.com/go-xorm/xorm"
+)
+
+func cleanUnlinkedWebhookAndHookTasks(x *xorm.Engine) error {
+	_, err := x.Exec(`DELETE FROM webhook WHERE (SELECT COUNT(*) FROM repository WHERE id = webhook.repo_id)=0;DELETE FROM hook_task WHERE (SELECT COUNT(*) FROM repository WHERE id = hook_task.repo_id)=0;`)
+	return err
+}