diff --git a/backend/pnpm-lock.yaml b/backend/pnpm-lock.yaml
index 490946b..2d5c4ac 100644
--- a/backend/pnpm-lock.yaml
+++ b/backend/pnpm-lock.yaml
@@ -4967,6 +4967,7 @@ snapshots:
       keyv: 5.6.0
       rxjs: 7.8.2
 
+  '@nestjs/cli@11.0.16(@swc/cli@0.6.0(@swc/core@1.15.11)(chokidar@4.0.3))(@swc/core@1.15.11)(@types/node@22.19.11)':
   '@nestjs/cli@11.0.16(@swc/cli@0.6.0(@swc/core@1.15.11(@swc/helpers@0.5.20))(chokidar@4.0.3))(@swc/core@1.15.11(@swc/helpers@0.5.20))(@types/node@22.19.11)':
     dependencies:
       '@angular-devkit/core': 19.2.19(chokidar@4.0.3)
diff --git a/backend/src/auth/auth.service.spec.ts b/backend/src/auth/auth.service.spec.ts
index 1414074..b3f32fc 100644
--- a/backend/src/auth/auth.service.spec.ts
+++ b/backend/src/auth/auth.service.spec.ts
@@ -39,6 +39,13 @@ describe('AuthService', () => {
     const module: TestingModule = await Test.createTestingModule({
       providers: [
         AuthService,
+        {
+          provide: UserService,
+          useValue: { create: jest.fn(), findByEmail: jest.fn() },
+        },
+        {
+          provide: JwtService,
+          useValue: { sign: jest.fn(), verify: jest.fn() },
         { provide: UserService, useValue: userService },
         { provide: JwtService, useValue: jwtService },
         { provide: ConfigService, useValue: { get: jest.fn() } },
diff --git a/backend/src/certificates/certificates.service.spec.ts b/backend/src/certificates/certificates.service.spec.ts
index b410a13..6e33eca 100644
--- a/backend/src/certificates/certificates.service.spec.ts
+++ b/backend/src/certificates/certificates.service.spec.ts
@@ -9,6 +9,7 @@ import { NotificationsService } from 'src/notifications/notifications.service';
 import { ConfigService } from '@nestjs/config';
 import { EmailService } from 'src/email/email.service';
 
+const mockRepo = () => ({
 const now = new Date();
 
 const mockUser = {
@@ -41,6 +42,7 @@ const makeCertRepo = () => ({
   find: jest.fn(),
   create: jest.fn(),
   save: jest.fn(),
+});
   createQueryBuilder: jest.fn(),
 });
 
diff --git a/backend/src/courses/courses.service.spec.ts b/backend/src/courses/courses.service.spec.ts
index cc5e234..55a3e81 100644
--- a/backend/src/courses/courses.service.spec.ts
+++ b/backend/src/courses/courses.service.spec.ts
@@ -59,6 +59,25 @@ describe('CoursesService', () => {
     const module: TestingModule = await Test.createTestingModule({
       providers: [
         CoursesService,
+        { provide: getRepositoryToken(Course), useValue: mockRepo() },
+        {
+          provide: getRepositoryToken(CourseRegistration),
+          useValue: mockRepo(),
+        },
+        { provide: getRepositoryToken(Lesson), useValue: mockRepo() },
+        { provide: getRepositoryToken(Progress), useValue: mockRepo() },
+        {
+          provide: PaginationService,
+          useValue: {
+            paginate: jest.fn().mockResolvedValue({
+              data: [],
+              total: 0,
+              page: 1,
+              limit: 10,
+              totalPages: 0,
+            }),
+          },
+        },
         { provide: getRepositoryToken(Course), useValue: courseRepo },
         { provide: getRepositoryToken(CourseRegistration), useValue: regRepo },
         { provide: getRepositoryToken(Lesson), useValue: lessonRepo },
diff --git a/backend/src/notifications/entities/notification.entity.ts b/backend/src/notifications/entities/notification.entity.ts
index ba59a65..90ca809 100644
--- a/backend/src/notifications/entities/notification.entity.ts
+++ b/backend/src/notifications/entities/notification.entity.ts
@@ -15,6 +15,7 @@ export enum NotificationType {
   QUIZ_PASSED = 'QUIZ_PASSED',
   COURSE_COMPLETE = 'COURSE_COMPLETE',
   NEW_CONTENT = 'NEW_CONTENT',
+  STREAK_MILESTONE = 'STREAK_MILESTONE',
 }
 
 @Entity('notifications')
diff --git a/backend/src/progress/progress.service.ts b/backend/src/progress/progress.service.ts
index 9eb4e45..31dd7f6 100644
--- a/backend/src/progress/progress.service.ts
+++ b/backend/src/progress/progress.service.ts
@@ -12,6 +12,7 @@ import {
   XP_LESSON_COMPLETE,
 } from 'src/rewards/rewards.service';
 import { XpRewardReason } from 'src/rewards/entities/reward-history.entity';
+import { StreakService } from 'src/users/streak.service';
 
 @Injectable()
 export class ProgressService {
@@ -23,6 +24,7 @@ export class ProgressService {
     private readonly certificateService: CertificateService,
     private readonly notificationsService: NotificationsService,
     private readonly rewardsService: RewardsService,
+    private readonly streakService: StreakService,
   ) {}
 
   /**
@@ -70,6 +72,7 @@ export class ProgressService {
         'You completed a lesson.',
         `/courses/${courseId}/lessons/${lessonId}`,
       );
+      await this.streakService.updateStreak(userId);
     }
 
     const allLessonsCompleted = await this.checkAllLessonsCompleted(
diff --git a/backend/src/quizzes/quizzes.service.ts b/backend/src/quizzes/quizzes.service.ts
index ba201d4..19f1c50 100644
--- a/backend/src/quizzes/quizzes.service.ts
+++ b/backend/src/quizzes/quizzes.service.ts
@@ -18,6 +18,7 @@ import { NotificationType } from 'src/notifications/entities/notification.entity
 import { RewardsService } from 'src/rewards/rewards.service';
 import { XP_QUIZ_PASS } from 'src/rewards/rewards.service';
 import { XpRewardReason } from 'src/rewards/entities/reward-history.entity';
+import { StreakService } from 'src/users/streak.service';
 
 @Injectable()
 export class QuizzesService {
@@ -32,6 +33,7 @@ export class QuizzesService {
     private quizSubmissionRepository: Repository<QuizSubmission>,
     private readonly notificationsService: NotificationsService,
     private readonly rewardsService: RewardsService,
+    private readonly streakService: StreakService,
   ) {}
 
   async create(createQuizDto: CreateQuizDto): Promise<Quiz> {
@@ -234,6 +236,7 @@ export class QuizzesService {
         `You passed the quiz "${quiz.title}".`,
         `/courses/lessons/${quiz.lessonId}`,
       );
+      await this.streakService.updateStreak(userId);
     }
 
     return savedSubmission;
diff --git a/backend/src/rewards/entities/reward-history.entity.ts b/backend/src/rewards/entities/reward-history.entity.ts
index fd19add..4acf519 100644
--- a/backend/src/rewards/entities/reward-history.entity.ts
+++ b/backend/src/rewards/entities/reward-history.entity.ts
@@ -12,6 +12,7 @@ export enum XpRewardReason {
   LESSON_COMPLETE = 'LESSON_COMPLETE',
   QUIZ_PASS = 'QUIZ_PASS',
   COURSE_COMPLETE = 'COURSE_COMPLETE',
+  STREAK_MILESTONE = 'STREAK_MILESTONE',
 }
 
 @Entity('reward_history')
diff --git a/backend/src/users/entities/user.entity.ts b/backend/src/users/entities/user.entity.ts
index 661ea3d..c66c4db 100644
--- a/backend/src/users/entities/user.entity.ts
+++ b/backend/src/users/entities/user.entity.ts
@@ -60,6 +60,12 @@ export class User {
   @Column({ type: 'int', default: 0 })
   streak: number;
 
+  @Column({ type: 'int', default: 0 })
+  longestStreak: number;
+
+  @Column({ type: 'datetime', nullable: true })
+  lastActiveAt: Date;
+
   @Column({ nullable: true })
   @Exclude()
   resetToken: string;
diff --git a/backend/src/users/streak.service.ts b/backend/src/users/streak.service.ts
new file mode 100644
index 0000000..8b2223f
--- /dev/null
+++ b/backend/src/users/streak.service.ts
@@ -0,0 +1,135 @@
+import { Injectable } from '@nestjs/common';
+import { InjectRepository } from '@nestjs/typeorm';
+import { Repository, LessThan } from 'typeorm';
+import { Cron, CronExpression } from '@nestjs/schedule';
+import { User } from './entities/user.entity';
+import { RewardsService } from '../rewards/rewards.service';
+import { NotificationsService } from '../notifications/notifications.service';
+import { NotificationType } from '../notifications/entities/notification.entity';
+import { XpRewardReason } from '../rewards/entities/reward-history.entity';
+
+@Injectable()
+export class StreakService {
+  constructor(
+    @InjectRepository(User)
+    private readonly userRepository: Repository<User>,
+    private readonly rewardsService: RewardsService,
+    private readonly notificationsService: NotificationsService,
+  ) {}
+
+  /**
+   * Updates the user's streak based on activity.
+   * - If lastActiveAt was yesterday, increment streak.
+   * - If lastActiveAt was more than 1 day ago, reset streak to 1.
+   * - If lastActiveAt is today, do nothing.
+   * - Update longestStreak if current streak exceeds it.
+   * - Check for milestones and award bonuses.
+   */
+  async updateStreak(userId: string): Promise<void> {
+    const user = await this.userRepository.findOne({
+      where: { id: userId },
+    });
+
+    if (!user) {
+      return;
+    }
+
+    const now = new Date();
+    const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
+    const yesterday = new Date(today);
+    yesterday.setDate(yesterday.getDate() - 1);
+
+    let newStreak = user.streak || 0;
+    let shouldUpdateLastActiveAt = true;
+
+    if (user.lastActiveAt) {
+      const lastActiveDate = new Date(user.lastActiveAt);
+      const lastActiveDay = new Date(
+        lastActiveDate.getFullYear(),
+        lastActiveDate.getMonth(),
+        lastActiveDate.getDate(),
+      );
+
+      if (lastActiveDay.getTime() === today.getTime()) {
+        // Already active today, no change
+        shouldUpdateLastActiveAt = false;
+      } else if (lastActiveDay.getTime() === yesterday.getTime()) {
+        // Active yesterday, increment streak
+        newStreak += 1;
+      } else {
+        // Gap in activity, reset to 1
+        newStreak = 1;
+      }
+    } else {
+      // First activity, start streak at 1
+      newStreak = 1;
+    }
+
+    // Update longestStreak if needed
+    if (newStreak > (user.longestStreak || 0)) {
+      user.longestStreak = newStreak;
+    }
+
+    user.streak = newStreak;
+
+    if (shouldUpdateLastActiveAt) {
+      user.lastActiveAt = now;
+    }
+
+    await this.userRepository.save(user);
+
+    // Check for streak milestones
+    await this.checkStreakMilestones(userId, newStreak);
+  }
+
+  /**
+   * Checks if the current streak hits a milestone and awards bonus XP and notification.
+   */
+  private async checkStreakMilestones(
+    userId: string,
+    streak: number,
+  ): Promise<void> {
+    const milestones = [
+      { days: 3, xp: 15 },
+      { days: 7, xp: 50 },
+      { days: 14, xp: 100 },
+      { days: 30, xp: 200 },
+    ];
+
+    const milestone = milestones.find((m) => m.days === streak);
+    if (milestone) {
+      await this.rewardsService.awardXP(
+        userId,
+        milestone.xp,
+        XpRewardReason.STREAK_MILESTONE,
+      );
+      await this.notificationsService.createNotification(
+        userId,
+        NotificationType.STREAK_MILESTONE,
+        `Congratulations! You've reached a ${streak}-day learning streak and earned ${milestone.xp} bonus XP!`,
+      );
+    }
+  }
+
+  /**
+   * Daily cron job to reset streaks for users inactive for more than 48 hours.
+   */
+  @Cron(CronExpression.EVERY_DAY_AT_MIDNIGHT)
+  async resetInactiveStreaks(): Promise<void> {
+    const cutoff = new Date();
+    cutoff.setHours(cutoff.getHours() - 48);
+
+    const usersToReset = await this.userRepository
+      .createQueryBuilder('user')
+      .where('user.streak > 0')
+      .andWhere('user.lastActiveAt < :cutoff OR user.lastActiveAt IS NULL', {
+        cutoff,
+      })
+      .getMany();
+
+    for (const user of usersToReset) {
+      user.streak = 0;
+      await this.userRepository.save(user);
+    }
+  }
+}
diff --git a/backend/src/users/users.controller.ts b/backend/src/users/users.controller.ts
index 42b81b7..d903dd1 100644
--- a/backend/src/users/users.controller.ts
+++ b/backend/src/users/users.controller.ts
@@ -113,6 +113,8 @@ export class UsersController {
     certificateCount: number;
     xp: number;
     streak: number;
+    longestStreak: number;
+    lastActiveAt: Date | null;
     badgesCount: number;
     rank: number;
   }> {
diff --git a/backend/src/users/users.module.ts b/backend/src/users/users.module.ts
index b87955a..92a4b00 100644
--- a/backend/src/users/users.module.ts
+++ b/backend/src/users/users.module.ts
@@ -9,6 +9,7 @@ import { CoursesModule } from '../courses/courses.module';
 import { Certificate } from '../certificates/entities/certificate.entity';
 import { UserBadge } from '../rewards/entities/user-badge.entity';
 import { CourseRegistration } from '../courses/entities/course-registration.entity';
+import { StreakService } from './streak.service';
 
 @Module({
   imports: [
@@ -22,7 +23,7 @@ import { CourseRegistration } from '../courses/entities/course-registration.enti
     forwardRef(() => CoursesModule),
   ],
   controllers: [UsersController],
-  providers: [UserService],
-  exports: [UserService],
+  providers: [UserService, StreakService],
+  exports: [UserService, StreakService],
 })
 export class UsersModule {}
diff --git a/backend/src/users/users.service.ts b/backend/src/users/users.service.ts
index 523f2d0..18d94eb 100644
--- a/backend/src/users/users.service.ts
+++ b/backend/src/users/users.service.ts
@@ -247,6 +247,8 @@ export class UserService {
     certificateCount: number;
     xp: number;
     streak: number;
+    longestStreak: number;
+    lastActiveAt: Date | null;
     badgesCount: number;
     rank: number;
   }> {
@@ -269,6 +271,8 @@ export class UserService {
       certificateCount,
       xp: resolvedXp,
       streak: user.streak ?? 0,
+      longestStreak: user.longestStreak ?? 0,
+      lastActiveAt: user.lastActiveAt ?? null,
       badgesCount,
       rank: usersAhead + 1,
     };
diff --git a/frontend/contexts/user-context.tsx b/frontend/contexts/user-context.tsx
index 298e35c..8cd29a6 100644
--- a/frontend/contexts/user-context.tsx
+++ b/frontend/contexts/user-context.tsx
@@ -27,8 +27,14 @@ export interface LearningStats {
 
 export interface UserStats {
   courseCount: number;
+  completedCourseCount: number;
   certificateCount: number;
   xp: number;
+  streak: number;
+  longestStreak: number;
+  lastActiveAt: string | null;
+  badgesCount: number;
+  rank: number;
 }
 
 export interface NotificationPreferences {