diff --git a/Backend/src/controllers/CoursesInstructorController.ts b/Backend/src/controllers/CoursesInstructorController.ts
index a0f956c7..3be4ee47 100644
--- a/Backend/src/controllers/CoursesInstructorController.ts
+++ b/Backend/src/controllers/CoursesInstructorController.ts
@@ -23,6 +23,7 @@ import {
     GetEnrolledStudentDetailResponse,
     GetCourseApprovalHistoryResponse,
     setCourseDraftResponse,
+    CloneCourseResponse,
 } from '../types/CoursesInstructor.types';
 import { CreateCourseValidator } from "../validators/CoursesInstructor.validator";
 
@@ -178,6 +179,33 @@ export class CoursesInstructorController {
         return await CoursesInstructorService.deleteCourse(token, courseId);
     }
 
+    /**
+     * คัดลอกคอร์ส (Clone Course)
+     * Clone an existing course to a new one with copied chapters, lessons, quizzes, and attachments
+     * @param courseId - รหัสคอร์สต้นฉบับ / Source Course ID
+     * @param body - ชื่อคอร์สใหม่ / New course title
+     */
+    @Post('{courseId}/clone')
+    @Security('jwt', ['instructor'])
+    @SuccessResponse('201', 'Course cloned successfully')
+    @Response('401', 'Invalid or expired token')
+    @Response('403', 'Not an instructor of this course')
+    @Response('404', 'Course not found')
+    public async cloneCourse(
+        @Request() request: any,
+        @Path() courseId: number,
+        @Body() body: { title: { th: string; en: string } }
+    ): Promise<CloneCourseResponse> {
+        const token = request.headers.authorization?.replace('Bearer ', '');
+        if (!token) throw new ValidationError('No token provided');
+
+        return await CoursesInstructorService.cloneCourse({
+            token,
+            course_id: courseId,
+            title: body.title
+        });
+    }
+
     /**
      * ส่งคอร์สเพื่อขออนุมัติจากแอดมิน
      * Submit course for admin review and approval
diff --git a/Backend/src/services/CoursesInstructor.service.ts b/Backend/src/services/CoursesInstructor.service.ts
index a2530033..e1b40d0c 100644
--- a/Backend/src/services/CoursesInstructor.service.ts
+++ b/Backend/src/services/CoursesInstructor.service.ts
@@ -34,6 +34,8 @@ import {
     GetEnrolledStudentDetailInput,
     GetEnrolledStudentDetailResponse,
     GetCourseApprovalHistoryResponse,
+    CloneCourseInput,
+    CloneCourseResponse,
     setCourseDraft,
     setCourseDraftResponse,
 } from "../types/CoursesInstructor.types";
@@ -1446,4 +1448,228 @@ export class CoursesInstructorService {
             throw error;
         }
     }
+
+    /**
+     * Clone a course (including chapters, lessons, quizzes, attachments)
+     */
+    static async cloneCourse(input: CloneCourseInput): Promise<CloneCourseResponse> {
+        try {
+            const { token, course_id, title } = input;
+            const decoded = jwt.verify(token, config.jwt.secret) as { id: number };
+
+            // Validate instructor
+            const courseInstructor = await this.validateCourseInstructor(token, course_id);
+            if (!courseInstructor) {
+                throw new ForbiddenError('You are not an instructor of this course');
+            }
+
+            // Fetch original course with all relations
+            const originalCourse = await prisma.course.findUnique({
+                where: { id: course_id },
+                include: {
+                    chapters: {
+                        orderBy: { sort_order: 'asc' },
+                        include: {
+                            lessons: {
+                                orderBy: { sort_order: 'asc' },
+                                include: {
+                                    attachments: true,
+                                    quiz: {
+                                        include: {
+                                            questions: {
+                                                include: {
+                                                    choices: true
+                                                }
+                                            }
+                                        }
+                                    }
+                                }
+                            }
+                        }
+                    }
+                }
+            });
+
+            if (!originalCourse) {
+                throw new NotFoundError('Course not found');
+            }
+
+            // Use transaction for atomic creation
+            const newCourse = await prisma.$transaction(async (tx) => {
+                // 1. Create new Course
+                const createdCourse = await tx.course.create({
+                    data: {
+                        title: title as Prisma.InputJsonValue,
+                        slug: `${originalCourse.slug}-clone-${Date.now()}`, // Temporary slug
+                        description: originalCourse.description ?? Prisma.JsonNull,
+                        thumbnail_url: originalCourse.thumbnail_url,
+                        category_id: originalCourse.category_id,
+                        price: originalCourse.price,
+                        is_free: originalCourse.is_free,
+                        have_certificate: originalCourse.have_certificate,
+                        status: 'DRAFT', // Reset status
+                        created_by: decoded.id
+                    }
+                });
+
+                // 2. Add Instructor (Requester as primary)
+                await tx.courseInstructor.create({
+                    data: {
+                        course_id: createdCourse.id,
+                        user_id: decoded.id,
+                        is_primary: true
+                    }
+                });
+
+                // Mapping for oldLessonId -> newLessonId for prerequisites
+                const lessonIdMap = new Map<number, number>();
+                const lessonsToUpdatePrerequisites: { newLessonId: number; oldPrerequisites: number[] }[] = [];
+
+                // 3. Clone Chapters and Lessons
+                for (const chapter of originalCourse.chapters) {
+                    const newChapter = await tx.chapter.create({
+                        data: {
+                            course_id: createdCourse.id,
+                            title: chapter.title as Prisma.InputJsonValue,
+                            description: chapter.description ?? Prisma.JsonNull,
+                            sort_order: chapter.sort_order,
+                            is_published: chapter.is_published
+                        }
+                    });
+
+                    for (const lesson of chapter.lessons) {
+                        const newLesson = await tx.lesson.create({
+                            data: {
+                                chapter_id: newChapter.id,
+                                title: lesson.title as Prisma.InputJsonValue,
+                                content: lesson.content ?? Prisma.JsonNull,
+                                type: lesson.type,
+                                sort_order: lesson.sort_order,
+                                is_published: lesson.is_published,
+                                duration_minutes: lesson.duration_minutes,
+                                prerequisite_lesson_ids: Prisma.JsonNull // Will update later
+                            }
+                        });
+
+                        lessonIdMap.set(lesson.id, newLesson.id);
+
+                        // Store prerequisites for later update
+                        if (Array.isArray(lesson.prerequisite_lesson_ids) && lesson.prerequisite_lesson_ids.length > 0) {
+                            lessonsToUpdatePrerequisites.push({
+                                newLessonId: newLesson.id,
+                                oldPrerequisites: lesson.prerequisite_lesson_ids as number[]
+                            });
+                        }
+
+                        // Clone Attachments
+                        if (lesson.attachments && lesson.attachments.length > 0) {
+                            await tx.lessonAttachment.createMany({
+                                data: lesson.attachments.map(att => ({
+                                    lesson_id: newLesson.id,
+                                    file_name: att.file_name,
+                                    file_path: att.file_path, // Reuse file path
+                                    file_size: att.file_size,
+                                    mime_type: att.mime_type,
+                                    sort_order: att.sort_order,
+                                    description: att.description ?? Prisma.JsonNull
+                                }))
+                            });
+                        }
+
+                        // Clone Quiz
+                        if (lesson.quiz) {
+                            const newQuiz = await tx.quiz.create({
+                                data: {
+                                    lesson_id: newLesson.id,
+                                    title: lesson.quiz.title as Prisma.InputJsonValue,
+                                    description: lesson.quiz.description ?? Prisma.JsonNull,
+                                    passing_score: lesson.quiz.passing_score,
+                                    allow_multiple_attempts: lesson.quiz.allow_multiple_attempts,
+                                    time_limit: lesson.quiz.time_limit,
+                                    shuffle_questions: lesson.quiz.shuffle_questions,
+                                    shuffle_choices: lesson.quiz.shuffle_choices,
+                                    show_answers_after_completion: lesson.quiz.show_answers_after_completion,
+                                    created_by: decoded.id
+                                }
+                            });
+
+                            for (const question of lesson.quiz.questions) {
+                                await tx.question.create({
+                                    data: {
+                                        quiz_id: newQuiz.id,
+                                        question: question.question as Prisma.InputJsonValue,
+                                        explanation: question.explanation ?? Prisma.JsonNull,
+                                        question_type: question.question_type,
+                                        score: question.score,
+                                        sort_order: question.sort_order,
+                                        choices: {
+                                            create: question.choices.map(choice => ({
+                                                text: choice.text as Prisma.InputJsonValue,
+                                                is_correct: choice.is_correct,
+                                                sort_order: choice.sort_order
+                                            }))
+                                        }
+                                    }
+                                });
+                            }
+                        }
+                    }
+                }
+
+                // 4. Update Prerequisites
+                for (const item of lessonsToUpdatePrerequisites) {
+                    const newPrerequisites = item.oldPrerequisites
+                        .map(oldId => lessonIdMap.get(oldId))
+                        .filter((id): id is number => id !== undefined);
+
+                    if (newPrerequisites.length > 0) {
+                        await tx.lesson.update({
+                            where: { id: item.newLessonId },
+                            data: {
+                                prerequisite_lesson_ids: newPrerequisites
+                            }
+                        });
+                    }
+                }
+
+                return createdCourse;
+            });
+
+            await auditService.logSync({
+                userId: decoded.id,
+                action: AuditAction.CREATE,
+                entityType: 'Course',
+                entityId: newCourse.id,
+                metadata: {
+                    operation: 'clone_course',
+                    original_course_id: course_id,
+                    new_course_id: newCourse.id
+                }
+            });
+
+            return {
+                code: 201,
+                message: 'Course cloned successfully',
+                data: {
+                    id: newCourse.id,
+                    title: newCourse.title as { th: string; en: string }
+                }
+            };
+
+        } catch (error) {
+            logger.error(`Error cloning course: ${error}`);
+            const decoded = jwt.decode(input.token) as { id: number } | null;
+            await auditService.logSync({
+                userId: decoded?.id || 0,
+                action: AuditAction.ERROR,
+                entityType: 'Course',
+                entityId: input.course_id,
+                metadata: {
+                    operation: 'clone_course',
+                    error: error instanceof Error ? error.message : String(error)
+                }
+            });
+            throw error;
+        }
+    }
 }
diff --git a/Backend/src/services/courses.service.ts b/Backend/src/services/courses.service.ts
index 0700a7fa..a0d96a45 100644
--- a/Backend/src/services/courses.service.ts
+++ b/Backend/src/services/courses.service.ts
@@ -104,6 +104,20 @@ export class CoursesService {
                 where: {
                     id,
                     status: 'APPROVED' // Only show approved courses to students
+                },
+                include: {
+                    chapters: {
+                        select: {
+                            id: true,
+                            title: true,
+                            lessons: {
+                                select: {
+                                    id: true,
+                                    title: true,
+                                }
+                            }
+                        }
+                    }
                 }
             });
 
diff --git a/Backend/src/types/CoursesInstructor.types.ts b/Backend/src/types/CoursesInstructor.types.ts
index e31e80fc..cc4aa149 100644
--- a/Backend/src/types/CoursesInstructor.types.ts
+++ b/Backend/src/types/CoursesInstructor.types.ts
@@ -433,3 +433,18 @@ export interface GetCourseApprovalHistoryResponse {
         approval_history: ApprovalHistoryItem[];
     };
 }
+
+export interface CloneCourseInput {
+    token: string;
+    course_id: number;
+    title: MultiLanguageText;
+}
+
+export interface CloneCourseResponse {
+    code: number;
+    message: string;
+    data: {
+        id: number;
+        title: MultiLanguageText;
+    };
+}