diff --git a/.server-changes/project-alert-channel-id-index.md b/.server-changes/project-alert-channel-id-index.md
new file mode 100644
index 0000000000..c9000c73f4
--- /dev/null
+++ b/.server-changes/project-alert-channel-id-index.md
@@ -0,0 +1,6 @@
+---
+area: webapp
+type: improvement
+---
+
+Deleting an alert channel is now fast and no longer slows down as a project builds up alert history.
diff --git a/internal-packages/database/prisma/migrations/20260810120000_add_project_alert_channel_id_index/migration.sql b/internal-packages/database/prisma/migrations/20260810120000_add_project_alert_channel_id_index/migration.sql
new file mode 100644
index 0000000000..aada1a7ba3
--- /dev/null
+++ b/internal-packages/database/prisma/migrations/20260810120000_add_project_alert_channel_id_index/migration.sql
@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE INDEX CONCURRENTLY IF NOT EXISTS "ProjectAlert_channelId_idx" ON "public"."ProjectAlert"("channelId");
diff --git a/internal-packages/database/prisma/schema.prisma b/internal-packages/database/prisma/schema.prisma
index 545b025953..5ce51d0db4 100644
--- a/internal-packages/database/prisma/schema.prisma
+++ b/internal-packages/database/prisma/schema.prisma
@@ -2412,6 +2412,8 @@ model ProjectAlert {
 
   createdAt DateTime @default(now())
   updatedAt DateTime @updatedAt
+
+  @@index([channelId])
 }
 
 enum ProjectAlertType {