diff --git a/packages/prisma/migrations/20250108095727_assignment_reason_index/migration.sql b/packages/prisma/migrations/20250108095727_assignment_reason_index/migration.sql
new file mode 100644
index 0000000000..b00355cfa3
--- /dev/null
+++ b/packages/prisma/migrations/20250108095727_assignment_reason_index/migration.sql
@@ -0,0 +1,2 @@
+-- CreateIndex
+CREATE INDEX "AssignmentReason_bookingId_idx" ON "AssignmentReason"("bookingId");
diff --git a/packages/prisma/schema.prisma b/packages/prisma/schema.prisma
index 67ac4ebbca..8b4fe4b31a 100644
--- a/packages/prisma/schema.prisma
+++ b/packages/prisma/schema.prisma
@@ -1711,6 +1711,8 @@ model AssignmentReason {
   booking      Booking              @relation(fields: [bookingId], references: [id], onDelete: Cascade)
   reasonEnum   AssignmentReasonEnum
   reasonString String
+
+  @@index([bookingId])
 }
 
 enum EventTypeAutoTranslatedField {