diff --git a/Projects/Presentation/Timer/Sources/Container/TimerContainer.swift b/Projects/Presentation/Timer/Sources/Container/TimerContainer.swift
new file mode 100644
index 0000000..21fc0b7
--- /dev/null
+++ b/Projects/Presentation/Timer/Sources/Container/TimerContainer.swift
@@ -0,0 +1,235 @@
+//
+//  TimerContainer.swift
+//  Timer
+//
+//  Created by 홍석현 on 2025-11-10
+//  Copyright © 2025 DDD , Ltd., All rights reserved.
+//
+
+import Foundation
+import Combine
+import ActivityKit
+import UserNotifications
+import AVFoundation
+
+// MARK: - Timer Container (ViewModel)
+public final class TimerContainer: ObservableObject {
+    // MARK: - Published State
+    @Published public private(set) var state: TimerState
+
+    // MARK: - Private Properties
+    private let model: TimerModelProtocol
+    private let notificationService: TimerNotificationServiceProtocol
+    private var cancellables = Set<AnyCancellable>()
+    private var timerCancellable: AnyCancellable?
+    private var currentActivity: Activity<TimerActivityAttributes>?
+    private var audioPlayer: AVAudioPlayer?
+
+    // MARK: - Published Alert State
+    @Published public var showCompletionAlert: Bool = false
+
+    // MARK: - Initialization
+    public init(
+        model: TimerModelProtocol = TimerModel(),
+        notificationService: TimerNotificationServiceProtocol = TimerNotificationService(),
+        initialState: TimerState = TimerState()
+    ) {
+        self.model = model
+        self.notificationService = notificationService
+        self.state = initialState
+
+        // 알림 권한 요청
+        Task {
+            await notificationService.requestAuthorization()
+        }
+    }
+
+    // MARK: - Intent Processing
+    public func send(_ intent: TimerIntent) {
+        let (newState, sideEffect) = model.reduce(state: state, intent: intent)
+        state = newState
+
+        if let sideEffect = sideEffect {
+            handleSideEffect(sideEffect)
+        }
+    }
+
+    // MARK: - Side Effect Handling
+    private func handleSideEffect(_ sideEffect: TimerSideEffect) {
+        switch sideEffect {
+        case .startTimerTicking:
+            startTimer()
+            startLiveActivity()
+            scheduleNotification()
+
+        case .stopTimerTicking:
+            stopTimer()
+            updateLiveActivity()
+            cancelNotification()
+
+        case .playAlarm:
+            playAlarm()
+            endLiveActivity()
+            cancelNotification()
+
+        case .showCompletionAlert:
+            displayCompletionAlert()
+        }
+    }
+
+    // MARK: - Timer Management
+    private var tickCount: Int = 0
+
+    private func startTimer() {
+        stopTimer() // 기존 타이머 정리
+        tickCount = 0
+
+        // 애니메이션과 동기화를 위해 0.3초 지연
+        Task { @MainActor in
+            try? await Task.sleep(nanoseconds: 300_000_000) // 0.3초
+
+            self.timerCancellable = Timer.publish(every: 0.1, on: .main, in: .common)
+                .autoconnect()
+                .sink { [weak self] _ in
+                    guard let self = self else { return }
+
+                    // endDate 기반으로 남은 시간 계산 (백그라운드에서도 정확함)
+                    if let endDate = self.state.endDate {
+                        let remaining = endDate.timeIntervalSinceNow
+
+                        if remaining > 0 {
+                            self.send(.updateRemainingTime(remaining))
+
+                            // 1초마다 Live Activity 업데이트 (10틱 = 1초)
+                            self.tickCount += 1
+                            if self.tickCount >= 10 {
+                                self.updateLiveActivity()
+                                self.tickCount = 0
+                            }
+                        } else {
+                            self.stopTimer()
+                            self.send(.timerCompleted)
+                        }
+                    }
+                }
+        }
+    }
+
+    private func stopTimer() {
+        timerCancellable?.cancel()
+        timerCancellable = nil
+    }
+
+    // MARK: - Alarm & Notifications
+    private func playAlarm() {
+        // 시스템 사운드 재생 (진동 포함)
+        AudioServicesPlaySystemSound(SystemSoundID(kSystemSoundID_Vibrate))
+        AudioServicesPlaySystemSound(1005) // 알림 사운드
+
+        print("🔔 타이머 완료! 알람 울림")
+
+        // 완료 알림도 함께 표시
+        displayCompletionAlert()
+    }
+
+    private func displayCompletionAlert() {
+        Task { @MainActor in
+            self.showCompletionAlert = true
+        }
+        print("✅ 타이머 완료 알림")
+    }
+
+    // MARK: - Notification Management
+    private func scheduleNotification() {
+        guard let endDate = state.endDate else { return }
+        notificationService.scheduleNotification(endDate: endDate, totalTime: state.totalTime)
+    }
+
+    private func cancelNotification() {
+        notificationService.cancelNotification()
+    }
+
+    // MARK: - Live Activity Management
+    private func startLiveActivity() {
+        let authInfo = ActivityAuthorizationInfo()
+        guard authInfo.areActivitiesEnabled else {
+            print("❌ Live Activities가 비활성화되어 있습니다.")
+            return
+        }
+
+        if currentActivity != nil {
+            updateLiveActivity()
+            return
+        }
+
+        Task {
+            let contentState = TimerActivityAttributes.ContentState(
+                totalTime: state.totalTime,
+                remainingTime: state.remainingTime,
+                endDate: state.endDate,
+                isRunning: state.isRunning,
+                isPaused: state.isPaused
+            )
+
+            do {
+                let activity = try Activity<TimerActivityAttributes>.request(
+                    attributes: TimerActivityAttributes(),
+                    content: .init(state: contentState, staleDate: nil)
+                )
+                currentActivity = activity
+                print("✅ Timer Live Activity 시작: \(activity.id)")
+            } catch {
+                print("❌ Timer Live Activity 시작 실패: \(error)")
+            }
+        }
+    }
+
+    private func updateLiveActivity() {
+        guard let activity = currentActivity else { return }
+
+        Task {
+            let contentState = TimerActivityAttributes.ContentState(
+                totalTime: state.totalTime,
+                remainingTime: state.remainingTime,
+                endDate: state.endDate,
+                isRunning: state.isRunning,
+                isPaused: state.isPaused
+            )
+
+            let staleDate = Date().addingTimeInterval(2)
+            await activity.update(.init(state: contentState, staleDate: staleDate))
+        }
+    }
+
+    private func endLiveActivity() {
+        guard let activity = currentActivity else { return }
+
+        Task {
+            let finalState = TimerActivityAttributes.ContentState(
+                totalTime: state.totalTime,
+                remainingTime: 0,
+                endDate: nil,
+                isRunning: false,
+                isPaused: false
+            )
+
+            await activity.end(
+                .init(state: finalState, staleDate: nil),
+                dismissalPolicy: .default
+            )
+            currentActivity = nil
+            print("✅ Timer Live Activity 종료")
+        }
+    }
+
+    // MARK: - Cleanup
+    deinit {
+        stopTimer()
+        cancelNotification()
+        Task { @MainActor [weak self] in
+            if let activity = self?.currentActivity {
+                await activity.end(nil, dismissalPolicy: .immediate)
+            }
+        }
+    }
+}
diff --git a/Projects/Presentation/Timer/Sources/TimerIntent.swift b/Projects/Presentation/Timer/Sources/Intent/TimerIntent.swift
similarity index 90%
rename from Projects/Presentation/Timer/Sources/TimerIntent.swift
rename to Projects/Presentation/Timer/Sources/Intent/TimerIntent.swift
index d6a2812..efd29f2 100644
--- a/Projects/Presentation/Timer/Sources/TimerIntent.swift
+++ b/Projects/Presentation/Timer/Sources/Intent/TimerIntent.swift
@@ -18,5 +18,6 @@ public enum TimerIntent {
     case resumeTimer
     case cancelTimer
     case timerTick
+    case updateRemainingTime(TimeInterval)
     case timerCompleted
 }
diff --git a/Projects/Presentation/Timer/Sources/TimerModel.swift b/Projects/Presentation/Timer/Sources/Model/TimerModel.swift
similarity index 82%
rename from Projects/Presentation/Timer/Sources/TimerModel.swift
rename to Projects/Presentation/Timer/Sources/Model/TimerModel.swift
index c94f82d..389197c 100644
--- a/Projects/Presentation/Timer/Sources/TimerModel.swift
+++ b/Projects/Presentation/Timer/Sources/Model/TimerModel.swift
@@ -40,20 +40,24 @@ public final class TimerModel: TimerModelProtocol {
             newState.remainingTime = TimeInterval(totalSeconds)
             newState.progress = 1.0
             newState.timerStatus = .running
+            newState.endDate = Date().addingTimeInterval(TimeInterval(totalSeconds))
             sideEffect = .startTimerTicking
 
         case .pauseTimer:
             newState.timerStatus = .paused
+            newState.endDate = nil
             sideEffect = .stopTimerTicking
 
         case .resumeTimer:
             newState.timerStatus = .running
+            newState.endDate = Date().addingTimeInterval(state.remainingTime)
             sideEffect = .startTimerTicking
 
         case .cancelTimer:
             newState.timerStatus = .idle
             newState.remainingTime = 0
             newState.progress = 1.0
+            newState.endDate = nil
             sideEffect = .stopTimerTicking
 
         case .timerTick:
@@ -62,10 +66,15 @@ public final class TimerModel: TimerModelProtocol {
                 newState.progress = state.totalTime > 0 ? newState.remainingTime / state.totalTime : 0
             }
 
+        case .updateRemainingTime(let remaining):
+            newState.remainingTime = max(0, remaining)
+            newState.progress = state.totalTime > 0 ? newState.remainingTime / state.totalTime : 0
+
         case .timerCompleted:
             newState.timerStatus = .idle
             newState.remainingTime = 0
             newState.progress = 1.0
+            newState.endDate = nil
             sideEffect = .playAlarm
         }
 
diff --git a/Projects/Presentation/Timer/Sources/TimerSideEffect.swift b/Projects/Presentation/Timer/Sources/Model/TimerSideEffect.swift
similarity index 100%
rename from Projects/Presentation/Timer/Sources/TimerSideEffect.swift
rename to Projects/Presentation/Timer/Sources/Model/TimerSideEffect.swift
diff --git a/Projects/Presentation/Timer/Sources/TimerState.swift b/Projects/Presentation/Timer/Sources/Model/TimerState.swift
similarity index 94%
rename from Projects/Presentation/Timer/Sources/TimerState.swift
rename to Projects/Presentation/Timer/Sources/Model/TimerState.swift
index 8de9948..d277ada 100644
--- a/Projects/Presentation/Timer/Sources/TimerState.swift
+++ b/Projects/Presentation/Timer/Sources/Model/TimerState.swift
@@ -20,6 +20,7 @@ public struct TimerState: Equatable {
     public var remainingTime: TimeInterval
     public var totalTime: TimeInterval
     public var progress: Double
+    public var endDate: Date?
 
     public init(
         selectedHours: Int = 0,
@@ -28,7 +29,8 @@ public struct TimerState: Equatable {
         timerStatus: TimerStatus = .idle,
         remainingTime: TimeInterval = 0,
         totalTime: TimeInterval = 0,
-        progress: Double = 1.0
+        progress: Double = 1.0,
+        endDate: Date? = nil
     ) {
         self.selectedHours = selectedHours
         self.selectedMinutes = selectedMinutes
@@ -37,6 +39,7 @@ public struct TimerState: Equatable {
         self.remainingTime = remainingTime
         self.totalTime = totalTime
         self.progress = progress
+        self.endDate = endDate
     }
 }
 
diff --git a/Projects/Presentation/Timer/Sources/Service/TimerNotificationService.swift b/Projects/Presentation/Timer/Sources/Service/TimerNotificationService.swift
new file mode 100644
index 0000000..f8ab4a4
--- /dev/null
+++ b/Projects/Presentation/Timer/Sources/Service/TimerNotificationService.swift
@@ -0,0 +1,88 @@
+//
+//  TimerNotificationService.swift
+//  Timer
+//
+//  Created by 홍석현 on 11/11/25.
+//
+
+import Foundation
+import UserNotifications
+
+public protocol TimerNotificationServiceProtocol {
+    func requestAuthorization() async -> Bool
+    func scheduleNotification(endDate: Date, totalTime: TimeInterval)
+    func cancelNotification()
+}
+
+public final class TimerNotificationService: TimerNotificationServiceProtocol {
+    private let notificationCenter = UNUserNotificationCenter.current()
+    private let notificationIdentifier = "com.wakeyalarm.timer.completion"
+
+    public init() {}
+
+    // MARK: - Authorization
+    public func requestAuthorization() async -> Bool {
+        do {
+            let granted = try await notificationCenter.requestAuthorization(options: [.alert, .sound, .badge])
+            if granted {
+                print("✅ 타이머 알림 권한 허용됨")
+            } else {
+                print("🚫 타이머 알림 권한 거부됨")
+            }
+            return granted
+        } catch {
+            print("❌ 타이머 알림 권한 요청 실패: \(error.localizedDescription)")
+            return false
+        }
+    }
+
+    // MARK: - Schedule
+    public func scheduleNotification(endDate: Date, totalTime: TimeInterval) {
+        let content = UNMutableNotificationContent()
+        content.title = "⏰ 타이머 완료"
+        content.body = formatTimeForMessage(totalTime) + " 타이머가 완료되었습니다"
+        content.sound = .default
+        content.categoryIdentifier = "TIMER_COMPLETION"
+
+        let timeInterval = endDate.timeIntervalSinceNow
+
+        // 최소 1초 이상이어야 알림이 예약됨
+        guard timeInterval > 1 else {
+            print("⚠️ 타이머 종료 시간이 너무 짧아 알림을 예약할 수 없습니다")
+            return
+        }
+
+        let trigger = UNTimeIntervalNotificationTrigger(timeInterval: timeInterval, repeats: false)
+        let request = UNNotificationRequest(identifier: notificationIdentifier, content: content, trigger: trigger)
+
+        notificationCenter.add(request) { error in
+            if let error = error {
+                print("❌ 타이머 알림 예약 실패: \(error.localizedDescription)")
+            } else {
+                print("✅ 타이머 알림 예약 완료: \(self.formatTimeForMessage(totalTime))")
+            }
+        }
+    }
+
+    // MARK: - Cancel
+    public func cancelNotification() {
+        notificationCenter.removePendingNotificationRequests(withIdentifiers: [notificationIdentifier])
+        notificationCenter.removeDeliveredNotifications(withIdentifiers: [notificationIdentifier])
+        print("🗑️ 타이머 알림 취소됨")
+    }
+
+    // MARK: - Helper
+    private func formatTimeForMessage(_ timeInterval: TimeInterval) -> String {
+        let hours = Int(timeInterval) / 3600
+        let minutes = (Int(timeInterval) % 3600) / 60
+        let seconds = Int(timeInterval) % 60
+
+        if hours > 0 {
+            return String(format: "%d시간 %d분 %d초", hours, minutes, seconds)
+        } else if minutes > 0 {
+            return String(format: "%d분 %d초", minutes, seconds)
+        } else {
+            return String(format: "%d초", seconds)
+        }
+    }
+}
diff --git a/Projects/Presentation/Timer/Sources/TimerContainer.swift b/Projects/Presentation/Timer/Sources/TimerContainer.swift
deleted file mode 100644
index 19ed87f..0000000
--- a/Projects/Presentation/Timer/Sources/TimerContainer.swift
+++ /dev/null
@@ -1,100 +0,0 @@
-//
-//  TimerContainer.swift
-//  Timer
-//
-//  Created by 홍석현 on 2025-11-10
-//  Copyright © 2025 DDD , Ltd., All rights reserved.
-//
-
-import Foundation
-import Combine
-
-// MARK: - Timer Container (ViewModel)
-public final class TimerContainer: ObservableObject {
-    // MARK: - Published State
-    @Published public private(set) var state: TimerState
-
-    // MARK: - Private Properties
-    private let model: TimerModelProtocol
-    private var cancellables = Set<AnyCancellable>()
-    private var timerCancellable: AnyCancellable?
-
-    // MARK: - Initialization
-    public init(
-        model: TimerModelProtocol = TimerModel(),
-        initialState: TimerState = TimerState()
-    ) {
-        self.model = model
-        self.state = initialState
-    }
-
-    // MARK: - Intent Processing
-    public func send(_ intent: TimerIntent) {
-        let (newState, sideEffect) = model.reduce(state: state, intent: intent)
-        state = newState
-
-        if let sideEffect = sideEffect {
-            handleSideEffect(sideEffect)
-        }
-    }
-
-    // MARK: - Side Effect Handling
-    private func handleSideEffect(_ sideEffect: TimerSideEffect) {
-        switch sideEffect {
-        case .startTimerTicking:
-            startTimer()
-
-        case .stopTimerTicking:
-            stopTimer()
-
-        case .playAlarm:
-            playAlarm()
-
-        case .showCompletionAlert:
-            showCompletionAlert()
-        }
-    }
-
-    // MARK: - Timer Management
-    private func startTimer() {
-        stopTimer() // 기존 타이머 정리
-
-        // 애니메이션과 동기화를 위해 0.3초 지연
-        Task { @MainActor in
-            try? await Task.sleep(nanoseconds: 300_000_000) // 0.3초
-
-            self.timerCancellable = Timer.publish(every: 0.1, on: .main, in: .common)
-                .autoconnect()
-                .sink { [weak self] _ in
-                    guard let self = self else { return }
-
-                    if self.state.remainingTime > 0 {
-                        self.send(.timerTick)
-                    } else {
-                        self.send(.timerCompleted)
-                    }
-                }
-        }
-    }
-
-    private func stopTimer() {
-        timerCancellable?.cancel()
-        timerCancellable = nil
-    }
-
-    // MARK: - Alarm & Notifications
-    private func playAlarm() {
-        // TODO: 알람 사운드 재생
-        print("🔔 타이머 완료! 알람 울림")
-    }
-
-    private func showCompletionAlert() {
-        // TODO: 완료 알림 표시
-        print("✅ 타이머 완료 알림")
-    }
-
-    // MARK: - Cleanup
-    deinit {
-        stopTimer()
-    }
-}
diff --git a/Projects/Presentation/Timer/Sources/TimerView.swift b/Projects/Presentation/Timer/Sources/TimerView.swift
index fc08567..cea1969 100644
--- a/Projects/Presentation/Timer/Sources/TimerView.swift
+++ b/Projects/Presentation/Timer/Sources/TimerView.swift
@@ -61,6 +61,13 @@ public struct TimerView: View {
             .padding(.bottom, 60)
         }
         .animation(.easeInOut(duration: 0.3), value: container.state.timerStatus)
+        .alert("타이머 완료", isPresented: $container.showCompletionAlert) {
+            Button("확인", role: .cancel) {
+                container.showCompletionAlert = false
+            }
+        } message: {
+            Text("설정한 타이머가 완료되었습니다.")
+        }
     }
 }
 
diff --git a/Projects/Presentation/Timer/Sources/Widget/TimerActivityAttributes.swift b/Projects/Presentation/Timer/Sources/Widget/TimerActivityAttributes.swift
new file mode 100644
index 0000000..d1c4bbb
--- /dev/null
+++ b/Projects/Presentation/Timer/Sources/Widget/TimerActivityAttributes.swift
@@ -0,0 +1,68 @@
+//
+//  TimerActivityAttributes.swift
+//  Timer
+//
+//  Created by 홍석현 on 11/11/25.
+//
+
+import Foundation
+import ActivityKit
+
+public struct TimerActivityAttributes: ActivityAttributes {
+    
+    public struct ContentState: Codable, Hashable {
+        public var totalTime: TimeInterval
+        public var remainingTime: TimeInterval
+        public var endDate: Date?
+        public var isRunning: Bool
+        public var isPaused: Bool
+        
+        public init(
+            totalTime: TimeInterval,
+            remainingTime: TimeInterval,
+            endDate: Date? = nil,
+            isRunning: Bool,
+            isPaused: Bool
+        ) {
+            self.totalTime = totalTime
+            self.remainingTime = remainingTime
+            self.endDate = endDate
+            self.isRunning = isRunning
+            self.isPaused = isPaused
+        }
+    }
+    
+    public init() {
+
+    }
+
+}
+
+// MARK: - Preview Support
+extension TimerActivityAttributes {
+    public static var preview: TimerActivityAttributes {
+        TimerActivityAttributes()
+    }
+}
+
+extension TimerActivityAttributes.ContentState {
+    public static var sample: TimerActivityAttributes.ContentState {
+        TimerActivityAttributes.ContentState(
+            totalTime: 300,
+            remainingTime: 185,
+            endDate: Date().addingTimeInterval(185),
+            isRunning: true,
+            isPaused: false
+        )
+    }
+
+    public static var almostDone: TimerActivityAttributes.ContentState {
+        TimerActivityAttributes.ContentState(
+            totalTime: 300,
+            remainingTime: 60,
+            endDate: Date().addingTimeInterval(60),
+            isRunning: true,
+            isPaused: false
+        )
+    }
+}
diff --git a/Projects/Presentation/Widget/Project.swift b/Projects/Presentation/Widget/Project.swift
index cc1a67d..98e3c57 100644
--- a/Projects/Presentation/Widget/Project.swift
+++ b/Projects/Presentation/Widget/Project.swift
@@ -17,7 +17,8 @@ let project = Project(
       sources: ["Sources/**"],
       resources: ["Resources/**"],
       dependencies: [
-        .Presentation(implements: .StopWatch)
+        .Presentation(implements: .StopWatch),
+        .Presentation(implements: .Timer)
         // WidgetKit과 SwiftUI는 시스템 프레임워크로 자동 링크됨
       ]
     )
diff --git a/Projects/Presentation/Widget/Sources/TimerLiveActivity.swift b/Projects/Presentation/Widget/Sources/TimerLiveActivity.swift
new file mode 100644
index 0000000..77bbc64
--- /dev/null
+++ b/Projects/Presentation/Widget/Sources/TimerLiveActivity.swift
@@ -0,0 +1,253 @@
+//
+//  TimerLiveActivity.swift
+//  Timer
+//
+//  Created by 홍석현 on 11/11/25.
+//
+
+import ActivityKit
+import WidgetKit
+import SwiftUI
+import Timer
+import DesignSystem
+
+public struct TimerLiveActivity: Widget {
+
+    public init() {}
+
+    public var body: some WidgetConfiguration {
+        ActivityConfiguration(for: TimerActivityAttributes.self) { context in
+            TimerLockScreenView(context: context)
+        } dynamicIsland: { context in
+            DynamicIsland {
+                DynamicIslandExpandedRegion(.leading) {
+                    TimerExpandedLeadingView()
+                }
+
+                DynamicIslandExpandedRegion(.trailing) {
+                    TimerExpandedTrailingView(context: context)
+                }
+
+                DynamicIslandExpandedRegion(.bottom) {
+                    TimerExpandedBottomView(context: context)
+                }
+            } compactLeading: {
+                TimerCompactLeadingView()
+            } compactTrailing: {
+                TimerCompactTrailingView(remainingTime: context.state.remainingTime)
+            } minimal: {
+                TimerMinimalView(isActive: context.state.isRunning && !context.state.isPaused)
+            }
+        }
+    }
+}
+
+// MARK: - Lock Screen Components
+
+private struct TimerLockScreenView: View {
+    let context: ActivityViewContext<TimerActivityAttributes>
+
+    var body: some View {
+        VStack(spacing: 12) {
+            TimerHeaderView(isActive: context.state.isRunning && !context.state.isPaused)
+            TimerMainTimeView(remainingTime: context.state.remainingTime)
+            Divider()
+            TimerTotalTimeRow(totalTime: context.state.totalTime)
+        }
+        .padding()
+        .background(
+            RoundedRectangle(cornerRadius: 16)
+                .fill(.ultraThinMaterial)
+        )
+    }
+}
+
+private struct TimerHeaderView: View {
+    let isActive: Bool
+
+    var body: some View {
+        HStack {
+            Image(systemName: "timer")
+                .foregroundColor(.blue)
+
+            Text("타이머")
+                .font(.headline)
+                .fontWeight(.medium)
+
+            Spacer()
+
+            StatusBadge(isActive: isActive)
+        }
+    }
+}
+
+private struct StatusBadge: View {
+    let isActive: Bool
+
+    var body: some View {
+        Text(isActive ? "실행 중" : "정지됨")
+            .font(.caption)
+            .padding(.horizontal, 8)
+            .padding(.vertical, 4)
+            .background(
+                Capsule()
+                    .fill(isActive ? .green.opacity(0.2) : .gray.opacity(0.2))
+            )
+            .foregroundColor(isActive ? .green : .secondary)
+    }
+}
+
+private struct TimerMainTimeView: View {
+    let remainingTime: TimeInterval
+
+    var body: some View {
+        VStack(spacing: 4) {
+            Text(formatTime(remainingTime))
+                .font(.system(size: 32, weight: .bold, design: .monospaced))
+                .foregroundColor(.primary)
+
+            Text("남은 시간")
+                .font(.caption)
+                .foregroundColor(.secondary)
+        }
+    }
+}
+
+private struct TimerTotalTimeRow: View {
+    let totalTime: TimeInterval
+
+    var body: some View {
+        HStack {
+            Text("전체 시간")
+                .font(.caption)
+                .foregroundColor(.secondary)
+            Spacer()
+            Text(formatTime(totalTime))
+                .font(.caption)
+                .fontWeight(.medium)
+                .monospacedDigit()
+                .foregroundColor(.primary)
+        }
+    }
+}
+
+// MARK: - Dynamic Island Components
+
+private struct TimerExpandedLeadingView: View {
+    var body: some View {
+        HStack {
+            Image(systemName: "timer")
+                .foregroundColor(.blue)
+
+            Text("타이머")
+                .font(.pretendardFont(family: .medium, size: 14))
+                .foregroundStyle(.whiteSmoke)
+        }
+        .padding(.leading, 10)
+    }
+}
+
+private struct TimerExpandedTrailingView: View {
+    let context: ActivityViewContext<TimerActivityAttributes>
+
+    var body: some View {
+        VStack(alignment: .trailing) {
+            Text(formatTime(context.state.remainingTime))
+                .font(.pretendardFont(family: .bold, size: 18))
+                .foregroundStyle(.whiteSmoke)
+                .monospacedDigit()
+
+            Text("남은 시간")
+                .font(.pretendardFont(family: .medium, size: 12))
+                .foregroundColor(.secondary)
+        }
+        .padding(.trailing, 10)
+    }
+}
+
+private struct TimerExpandedBottomView: View {
+    let context: ActivityViewContext<TimerActivityAttributes>
+
+    var body: some View {
+        HStack {
+            VStack(alignment: .leading) {
+                Text("전체 시간")
+                    .font(.pretendardFont(family: .medium, size: 12))
+                    .foregroundColor(.secondary)
+
+                Text(formatTime(context.state.totalTime))
+                    .font(.pretendardFont(family: .medium, size: 14))
+                    .monospacedDigit()
+            }
+
+            Spacer()
+
+            StatusIndicator(isActive: context.state.isRunning && !context.state.isPaused)
+        }
+        .padding(.horizontal, 10)
+    }
+}
+
+private struct StatusIndicator: View {
+    let isActive: Bool
+
+    var body: some View {
+        HStack(spacing: 4) {
+            Circle()
+                .fill(isActive ? .green : .gray)
+                .frame(width: 8, height: 8)
+
+            Text(isActive ? "실행 중" : "정지됨")
+                .font(.pretendardFont(family: .medium, size: 12))
+                .foregroundColor(.secondary)
+        }
+    }
+}
+
+private struct TimerCompactLeadingView: View {
+    var body: some View {
+        Image(systemName: "timer")
+            .foregroundColor(.blue)
+            .padding(.leading, 10)
+    }
+}
+
+private struct TimerCompactTrailingView: View {
+    let remainingTime: TimeInterval
+
+    var body: some View {
+        Text(formatTime(remainingTime))
+            .font(.pretendardFont(family: .medium, size: 12))
+            .monospacedDigit()
+            .padding(.trailing, 10)
+    }
+}
+
+private struct TimerMinimalView: View {
+    let isActive: Bool
+
+    var body: some View {
+        Image(systemName: isActive ? "play.fill" : "pause.fill")
+            .foregroundColor(isActive ? .green : .orange)
+    }
+}
+
+// MARK: - Helper Functions
+
+private func formatTime(_ timeInterval: TimeInterval) -> String {
+    let minutes = Int(timeInterval) / 60
+    let seconds = Int(timeInterval) % 60
+    return String(format: "%02d:%02d", minutes, seconds)
+}
+
+@available(iOS 17.0, *)
+#Preview(
+    "타이머 잠금 화면",
+    as: .content,
+    using: TimerActivityAttributes.preview
+) {
+    TimerLiveActivity()
+} contentStates: {
+    TimerActivityAttributes.ContentState.sample
+    TimerActivityAttributes.ContentState.almostDone
+}
diff --git a/Projects/Presentation/Widget/Sources/WakeyAlarmWidget.swift b/Projects/Presentation/Widget/Sources/WakeyAlarmWidget.swift
index 392e7d8..d588480 100644
--- a/Projects/Presentation/Widget/Sources/WakeyAlarmWidget.swift
+++ b/Projects/Presentation/Widget/Sources/WakeyAlarmWidget.swift
@@ -5,11 +5,7 @@ import SwiftUI
 @main
 struct WakeyAlarmWidgetBundle: WidgetBundle {
     var body: some Widget {
-        // iOS 16.1+ Live Activity 지원
-        #if canImport(ActivityKit)
-        if #available(iOS 16.1, *) {
-            StopWatchLiveActivity()
-        }
-        #endif
+        StopWatchLiveActivity()
+        TimerLiveActivity()
     }
 }