diff --git a/server/openapi.json b/server/openapi.json
index 058e934b7..f62062332 100644
--- a/server/openapi.json
+++ b/server/openapi.json
@@ -4657,6 +4657,11 @@
 									"repeat": {
 										"type": "number",
 										"minimum": 0
+									},
+									"expiry": {
+										"type": "string",
+										"nullable": true,
+										"format": "date-time"
 									}
 								},
 								"required": ["monitors", "name", "duration", "durationUnit", "start", "end", "repeat"]
@@ -5185,6 +5190,11 @@
 										"nullable": true,
 										"format": "date-time"
 									},
+									"expiry": {
+										"type": "string",
+										"nullable": true,
+										"format": "date-time"
+									},
 									"monitors": {
 										"type": "array",
 										"items": {
diff --git a/server/src/db/migration/0007_dropMaintenanceWindowExpiryIndex.ts b/server/src/db/migration/0007_dropMaintenanceWindowExpiryIndex.ts
deleted file mode 100644
index 38e55c0d7..000000000
--- a/server/src/db/migration/0007_dropMaintenanceWindowExpiryIndex.ts
+++ /dev/null
@@ -1,58 +0,0 @@
-import mongoose from "mongoose";
-import { logger } from "@/utils/logger.js";
-
-/**
- * Drops the TTL index on MaintenanceWindow.expiry and unsets the field on existing rows.
- *
- * Why: a previous version copied `end` into `expiry` for one-time windows. Combined with the
- * TTL index on `expiry`, this caused Mongo to silently delete rows whose `end` was in the past
- * at creation time (a common symptom for automation tools sending non-UTC timestamps). The
- * fix stops writing `expiry`; this migration removes the live exposure on existing installs.
- */
-export async function dropMaintenanceWindowExpiryIndex(): Promise<void> {
-	const SERVICE_NAME = "Migration:DropMaintenanceWindowExpiryIndex";
-
-	try {
-		logger.info({
-			service: SERVICE_NAME,
-			message: "Starting drop of MaintenanceWindow.expiry TTL index",
-		});
-
-		const db = mongoose.connection.db;
-		if (!db) {
-			throw new Error("Mongo connection not initialized");
-		}
-		const collection = db.collection("maintenancewindows");
-
-		const indexes = await collection.indexes();
-		const expiryIndex = indexes.find(
-			(idx) => idx.expireAfterSeconds !== undefined && idx.key && Object.keys(idx.key).length === 1 && idx.key.expiry === 1
-		);
-
-		if (expiryIndex?.name) {
-			await collection.dropIndex(expiryIndex.name);
-			logger.info({
-				service: SERVICE_NAME,
-				message: `Dropped TTL index ${expiryIndex.name} on MaintenanceWindow.expiry`,
-			});
-		} else {
-			logger.info({
-				service: SERVICE_NAME,
-				message: "No TTL index found on MaintenanceWindow.expiry",
-			});
-		}
-
-		const result = await collection.updateMany({ expiry: { $exists: true } }, { $unset: { expiry: "" } });
-		logger.info({
-			service: SERVICE_NAME,
-			message: `Unset expiry on ${result.modifiedCount} maintenance windows`,
-		});
-	} catch (error) {
-		const errorMessage = error instanceof Error ? error.message : String(error);
-		logger.error({
-			service: SERVICE_NAME,
-			message: `Error dropping expiry index: ${errorMessage}`,
-		});
-		throw error;
-	}
-}
diff --git a/server/src/db/migration/index.ts b/server/src/db/migration/index.ts
index fcf0cf1fb..5b74a96fc 100644
--- a/server/src/db/migration/index.ts
+++ b/server/src/db/migration/index.ts
@@ -5,7 +5,6 @@ import { fixInfrastructureThresholds } from "./0004_fixInfrastructureThresholds.
 import MigrationModel from "../models/Migration.js";
 import { migrateStatusPageTypeToArray } from "./0005_migrateStatusPageTypeToArray.js";
 import { cleanupDuplicateMonitorStatsForUniqueIndex } from "./0006_cleanupDuplicateMonitorStatsForUniqueIndex.js";
-import { dropMaintenanceWindowExpiryIndex } from "./0007_dropMaintenanceWindowExpiryIndex.js";
 import type { ILogger } from "@/utils/logger.js";
 
 type MigrationEntry = {
@@ -20,7 +19,6 @@ const migrations: MigrationEntry[] = [
 	{ name: "0004_fixInfrastructureThresholds", execute: fixInfrastructureThresholds },
 	{ name: "0005_migrateStatusPageTypeToArray", execute: migrateStatusPageTypeToArray },
 	{ name: "0006_cleanupDuplicateMonitorStatsForUniqueIndex", execute: cleanupDuplicateMonitorStatsForUniqueIndex },
-	{ name: "0007_dropMaintenanceWindowExpiryIndex", execute: dropMaintenanceWindowExpiryIndex },
 ];
 
 const runMigrations = async (logger?: ILogger) => {
diff --git a/server/src/db/models/MaintenanceWindow.ts b/server/src/db/models/MaintenanceWindow.ts
index 1fc9b5f4a..703c144c8 100644
--- a/server/src/db/models/MaintenanceWindow.ts
+++ b/server/src/db/models/MaintenanceWindow.ts
@@ -6,6 +6,7 @@ type MaintenanceWindowDocumentBase = Omit<MaintenanceWindow, "id" | "monitorId"
 	teamId: Types.ObjectId;
 	start: Date;
 	end: Date;
+	expiry?: Date;
 	createdAt: Date;
 	updatedAt: Date;
 };
@@ -49,6 +50,10 @@ const MaintenanceWindowSchema = new Schema<MaintenanceWindowDocument>(
 		end: {
 			type: Date,
 		},
+		expiry: {
+			type: Date,
+			index: { expires: "0s" },
+		},
 	},
 	{
 		timestamps: true,
diff --git a/server/src/repositories/maintenance-windows/MongoMaintenanceWindowsRepository.ts b/server/src/repositories/maintenance-windows/MongoMaintenanceWindowsRepository.ts
index 0cdda805e..ad96328c5 100644
--- a/server/src/repositories/maintenance-windows/MongoMaintenanceWindowsRepository.ts
+++ b/server/src/repositories/maintenance-windows/MongoMaintenanceWindowsRepository.ts
@@ -45,6 +45,11 @@ class MongoMaintenanceWindowsRepository implements IMaintenanceWindowsRepository
 
 	create = async (data: Partial<MaintenanceWindow>): Promise<MaintenanceWindow> => {
 		const maintenanceWindow = new MaintenanceWindowModel(data);
+
+		// If the maintenance window is a one time window, set the expiry to the end date
+		if (maintenanceWindow.repeat === 0) {
+			maintenanceWindow.expiry = maintenanceWindow.end;
+		}
 		const result = await maintenanceWindow.save();
 		return this.toEntity(result);
 	};
diff --git a/server/src/validation/maintenanceWindowValidation.ts b/server/src/validation/maintenanceWindowValidation.ts
index bdd11df5f..c53e39b20 100644
--- a/server/src/validation/maintenanceWindowValidation.ts
+++ b/server/src/validation/maintenanceWindowValidation.ts
@@ -18,6 +18,7 @@ export const createMaintenanceWindowBodyValidation = z
 		start: dateToString,
 		end: dateToString,
 		repeat: z.number().min(0, "Repeat must be a non-negative number"),
+		expiry: dateToString.optional(),
 	})
 	.strict()
 	.superRefine((data, ctx) => {
@@ -70,6 +71,7 @@ export const editMaintenanceByIdWindowBodyValidation = z
 		repeat: z.number().optional(),
 		start: dateToString.optional(),
 		end: dateToString.optional(),
+		expiry: dateToString.optional(),
 		monitors: z.array(z.string()).optional(),
 		duration: z.number().optional(),
 		durationUnit: z.enum(DurationUnits).optional(),