diff --git a/server/src/service/business/maintenanceWindowService.ts b/server/src/service/business/maintenanceWindowService.ts
index 5d7a05b7d..d198d1e9d 100644
--- a/server/src/service/business/maintenanceWindowService.ts
+++ b/server/src/service/business/maintenanceWindowService.ts
@@ -107,7 +107,7 @@ export class MaintenanceWindowService implements IMaintenanceWindowService {
 			});
 		}
 
-		await this.maintenanceWindowsRepository.create({
+		const created = await this.maintenanceWindowsRepository.create({
 			teamId,
 			monitorIds: monitorIDs,
 			name: name,
@@ -118,6 +118,10 @@ export class MaintenanceWindowService implements IMaintenanceWindowService {
 			start: start,
 			end: end,
 		});
+
+		if (isWindowActive(created)) {
+			await this.monitorsRepository.updateByIds(created.monitorIds, teamId, { status: "maintenance" });
+		}
 	};
 
 	getMaintenanceWindowById = async ({ id, teamId }: { id: string; teamId: string }) => {
diff --git a/server/test/unit/services/maintenanceWindowService.test.ts b/server/test/unit/services/maintenanceWindowService.test.ts
index a51fd5703..bee60d4ef 100644
--- a/server/test/unit/services/maintenanceWindowService.test.ts
+++ b/server/test/unit/services/maintenanceWindowService.test.ts
@@ -149,6 +149,26 @@ describe("MaintenanceWindowService", () => {
 			expect(maintenanceWindowsRepository.create).toHaveBeenCalledTimes(1);
 			expect(maintenanceWindowsRepository.create).toHaveBeenCalledWith(expect.objectContaining({ monitorIds: ["mon-1"] }));
 		});
+
+		it("flips monitors to maintenance when the created window is active", async () => {
+			const maintenanceWindowsRepository = createMaintenanceWindowsRepo();
+			(maintenanceWindowsRepository.create as jest.Mock).mockResolvedValue(makeActiveWindow({ monitorIds: ["mon-1", "mon-2"] }));
+			const { service, monitorsRepository } = createService({ maintenanceWindowsRepository });
+
+			await service.createMaintenanceWindow(defaultCreateParams);
+
+			expect(monitorsRepository.updateByIds).toHaveBeenCalledTimes(1);
+			expect(monitorsRepository.updateByIds).toHaveBeenCalledWith(["mon-1", "mon-2"], "team-1", { status: "maintenance" });
+		});
+
+		it("does not touch monitor status when the created window is inactive", async () => {
+			// default mock returns makeWindow() with past dates → inactive
+			const { service, monitorsRepository } = createService();
+
+			await service.createMaintenanceWindow(defaultCreateParams);
+
+			expect(monitorsRepository.updateByIds).not.toHaveBeenCalled();
+		});
 	});
 
 	// ── getMaintenanceWindowById ─────────────────────────────────────────────