diff --git a/build.gradle b/build.gradle
index 8e377f6..794395d 100644
--- a/build.gradle
+++ b/build.gradle
@@ -32,6 +32,7 @@ dependencies {
     testImplementation 'org.springframework.boot:spring-boot-starter-test'
     testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
     runtimeOnly 'com.mysql:mysql-connector-j'
+    implementation 'org.springframework.boot:spring-boot-starter-validation'
 }
 
 tasks.named('test') {
diff --git a/src/main/java/com/example/springbootassignment/controller/PostController.java b/src/main/java/com/example/springbootassignment/controller/PostController.java
new file mode 100644
index 0000000..7820d67
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/controller/PostController.java
@@ -0,0 +1,77 @@
+package com.example.springbootassignment.controller;
+
+import com.example.springbootassignment.dto.PostCreateRequest;
+import com.example.springbootassignment.dto.PostListResponse;
+import com.example.springbootassignment.dto.PostResponse;
+import com.example.springbootassignment.dto.PostUpdateRequest;
+import com.example.springbootassignment.service.PostService;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+@RestController
+@RequestMapping("/posts")
+public class PostController {
+
+    private final PostService postService;
+
+    public PostController(PostService postService) {
+        this.postService = postService;
+    }
+
+    /**
+     * 게시글 목록 조회
+     * GET /posts?page=1&size=10&sort=createdAt&order=desc
+     */
+    @GetMapping
+    public ResponseEntity<PostListResponse> getPostList(
+            @RequestParam(defaultValue = "1") int page,
+            @RequestParam(defaultValue = "10") int size,
+            @RequestParam(defaultValue = "createdAt") String sort,
+            @RequestParam(defaultValue = "desc") String order) {
+        PostListResponse response = postService.getPostList(page, size, sort, order);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 상세 조회
+     * GET /posts/{postId}
+     */
+    @GetMapping("/{postId}")
+    public ResponseEntity<PostResponse> getPostDetail(@PathVariable Long postId) {
+        PostResponse response = postService.getPostDetail(postId);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 작성
+     * POST /posts
+     */
+    @PostMapping
+    public ResponseEntity<PostResponse> createPost(@RequestBody PostCreateRequest request) {
+        PostResponse response = postService.createPost(request);
+        return ResponseEntity.status(HttpStatus.CREATED).body(response);
+    }
+
+    /**
+     * 게시글 수정
+     * PUT /posts/{postId}
+     */
+    @PutMapping("/{postId}")
+    public ResponseEntity<PostResponse> updatePost(
+            @PathVariable Long postId,
+            @RequestBody PostUpdateRequest request) {
+        PostResponse response = postService.updatePost(postId, request);
+        return ResponseEntity.ok(response);
+    }
+
+    /**
+     * 게시글 삭제
+     * DELETE /posts/{postId}
+     */
+    @DeleteMapping("/{postId}")
+    public ResponseEntity<Void> deletePost(@PathVariable Long postId) {
+        postService.deletePost(postId);
+        return ResponseEntity.noContent().build();
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/domain/post/entity/Post.java b/src/main/java/com/example/springbootassignment/domain/post/entity/Post.java
index 943c679..daca53e 100644
--- a/src/main/java/com/example/springbootassignment/domain/post/entity/Post.java
+++ b/src/main/java/com/example/springbootassignment/domain/post/entity/Post.java
@@ -13,7 +13,8 @@
 @Entity
 @Table(name = "posts")
 @Getter
-@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Setter
+@NoArgsConstructor
 public class Post {
 
     @Id
@@ -21,7 +22,7 @@ public class Post {
     private Long id;
 
     @ManyToOne(fetch = FetchType.LAZY)
-    @JoinColumn(name = "user_id", nullable = false)
+    @JoinColumn(name = "user_id", nullable = true)  // ← nullable = true로 변경
     private User user;
 
     @Column(nullable = false, length = 100)
@@ -52,4 +53,11 @@ public class Post {
 
     @OneToMany(mappedBy = "post", cascade = CascadeType.ALL)
     private List<Comment> comments = new ArrayList<>();
+
+    /**
+     * 조회수 증가
+     */
+    public void increaseViewCount() {
+        this.viewCount++;
+    }
 }
diff --git a/src/main/java/com/example/springbootassignment/domain/post/entity/PostRepository.java b/src/main/java/com/example/springbootassignment/domain/post/entity/PostRepository.java
new file mode 100644
index 0000000..badcfc8
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/domain/post/entity/PostRepository.java
@@ -0,0 +1,7 @@
+package com.example.springbootassignment.domain.post.entity;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+public interface PostRepository extends JpaRepository<Post, Long> {
+}
diff --git a/src/main/java/com/example/springbootassignment/dto/ErrorResponse.java b/src/main/java/com/example/springbootassignment/dto/ErrorResponse.java
new file mode 100644
index 0000000..2e1053d
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/dto/ErrorResponse.java
@@ -0,0 +1,16 @@
+package com.example.springbootassignment.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class ErrorResponse {
+    private String code;           // 에러 코드 (COMMON400, POST4041 등)
+    private String message;        // 사용자 친화적인 메시지
+    private String details;        // 상세 정보
+}
diff --git a/src/main/java/com/example/springbootassignment/dto/PostCreateRequest.java b/src/main/java/com/example/springbootassignment/dto/PostCreateRequest.java
new file mode 100644
index 0000000..fae0aaa
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/dto/PostCreateRequest.java
@@ -0,0 +1,18 @@
+package com.example.springbootassignment.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class PostCreateRequest {
+
+    @NotBlank(message = "제목은 필수 입력 사항입니다.")
+    private String title;
+
+    @NotBlank(message = "내용은 필수 입력 사항입니다.")
+    private String content;
+
+    private Long userId;
+}
diff --git a/src/main/java/com/example/springbootassignment/dto/PostListResponse.java b/src/main/java/com/example/springbootassignment/dto/PostListResponse.java
new file mode 100644
index 0000000..9553c86
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/dto/PostListResponse.java
@@ -0,0 +1,42 @@
+package com.example.springbootassignment.dto;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.springframework.data.domain.Page;
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class PostListResponse {
+
+    private List<Long> postId;
+    private List<String> title;
+    private List<String> nickname;
+    private List<LocalDateTime> createdAt;
+
+    /**
+     * Page<Post>를 PostListResponse로 변환
+     */
+    public static PostListResponse from(Page<Post> posts) {
+        PostListResponse response = new PostListResponse();
+        response.postId = posts.getContent().stream()
+                .map(Post::getId)
+                .toList();
+        response.title = posts.getContent().stream()
+                .map(Post::getTitle)
+                .toList();
+        response.nickname = posts.getContent().stream()
+                .map(post -> post.getUser() != null ? post.getUser().getNickname() : "unknown")
+                .toList();
+        response.createdAt = posts.getContent().stream()
+                .map(Post::getCreatedAt)
+                .toList();
+        return response;
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/dto/PostResponse.java b/src/main/java/com/example/springbootassignment/dto/PostResponse.java
new file mode 100644
index 0000000..b6cc429
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/dto/PostResponse.java
@@ -0,0 +1,34 @@
+package com.example.springbootassignment.dto;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import java.time.LocalDateTime;
+
+@Getter
+@Setter
+@NoArgsConstructor
+@AllArgsConstructor
+public class PostResponse {
+
+    private Long postId;
+    private String title;
+    private String content;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
+
+    /**
+     * Post Entity를 PostResponse DTO로 변환
+     */
+    public static PostResponse from(Post post) {
+        PostResponse response = new PostResponse();
+        response.postId = post.getId();
+        response.title = post.getTitle();
+        response.content = post.getContent();
+        response.createdAt = post.getCreatedAt();
+        response.updatedAt = post.getUpdatedAt();
+        return response;
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/dto/PostUpdateRequest.java b/src/main/java/com/example/springbootassignment/dto/PostUpdateRequest.java
new file mode 100644
index 0000000..e548bee
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/dto/PostUpdateRequest.java
@@ -0,0 +1,16 @@
+package com.example.springbootassignment.dto;
+
+import jakarta.validation.constraints.NotBlank;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+public class PostUpdateRequest {
+
+    @NotBlank(message = "제목은 필수 입력 사항입니다.")
+    private String title;
+
+    @NotBlank(message = "내용은 필수 입력 사항입니다.")
+    private String content;
+}
diff --git a/src/main/java/com/example/springbootassignment/exception/CommentNotFoundException.java b/src/main/java/com/example/springbootassignment/exception/CommentNotFoundException.java
new file mode 100644
index 0000000..c072836
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/exception/CommentNotFoundException.java
@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class CommentNotFoundException extends RuntimeException {
+    public CommentNotFoundException(Long commentId) {
+        super("존재하지 않는 댓글입니다. id: " + commentId);
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/exception/ForbiddenException.java b/src/main/java/com/example/springbootassignment/exception/ForbiddenException.java
new file mode 100644
index 0000000..09e8332
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/exception/ForbiddenException.java
@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class ForbiddenException extends RuntimeException {
+    public ForbiddenException(Long postId, Long userId) {
+        super("게시글 id: " + postId + "를(을) 수정/삭제할 권한이 없습니다. (사용자 id: " + userId + ")");
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/exception/GlobalExceptionHandler.java b/src/main/java/com/example/springbootassignment/exception/GlobalExceptionHandler.java
new file mode 100644
index 0000000..808aee6
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/exception/GlobalExceptionHandler.java
@@ -0,0 +1,97 @@
+package com.example.springbootassignment.exception;
+
+import com.example.springbootassignment.dto.ErrorResponse;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.ExceptionHandler;
+import org.springframework.web.bind.annotation.RestControllerAdvice;
+
+@RestControllerAdvice
+public class GlobalExceptionHandler {
+
+    /**
+     * 잘못된 요청 (400 Bad Request)
+     * - 제목이나 내용이 비어있는 경우
+     * - 유효하지 않은 입력값
+     */
+    @ExceptionHandler(IllegalArgumentException.class)
+    public ResponseEntity<ErrorResponse> handleIllegalArgumentException(IllegalArgumentException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON400",
+                "잘못된 요청입니다. 입력값을 확인해주세요.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(errorResponse);
+    }
+
+    /**
+     * 인증 오류 (401 Unauthorized)
+     * - 게시글 작성 시 필수 항목 누락
+     * - JWT 토큰 없음
+     */
+    @ExceptionHandler(UnauthorizedException.class)
+    public ResponseEntity<ErrorResponse> handleUnauthorizedException(UnauthorizedException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON401",
+                "인증이 필요합니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.UNAUTHORIZED).body(errorResponse);
+    }
+
+    /**
+     * 권한 오류 (403 Forbidden)
+     * - 자신이 쓴 글이 아닌데 수정/삭제 시도
+     */
+    @ExceptionHandler(ForbiddenException.class)
+    public ResponseEntity<ErrorResponse> handleForbiddenException(ForbiddenException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON403",
+                "접근 권한이 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.FORBIDDEN).body(errorResponse);
+    }
+
+    /**
+     * 게시글 조회 실패 (404 Not Found)
+     * - 존재하지 않는 게시글 ID로 조회/수정/삭제 시도
+     */
+    @ExceptionHandler(PostNotFoundException.class)
+    public ResponseEntity<ErrorResponse> handlePostNotFoundException(PostNotFoundException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "POST4041",
+                "게시글을 찾을 수 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorResponse);
+    }
+
+    /**
+     * 댓글 조회 실패 (404 Not Found)
+     * - 존재하지 않는 댓글 ID
+     */
+    @ExceptionHandler(CommentNotFoundException.class)
+    public ResponseEntity<ErrorResponse> handleCommentNotFoundException(CommentNotFoundException e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON404",
+                "댓글을 찾을 수 없습니다.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.NOT_FOUND).body(errorResponse);
+    }
+
+    /**
+     * 내부 서버 오류 (500 Internal Server Error)
+     * - 예상치 못한 오류
+     */
+    @ExceptionHandler(Exception.class)
+    public ResponseEntity<ErrorResponse> handleGeneralException(Exception e) {
+        ErrorResponse errorResponse = new ErrorResponse(
+                "COMMON500",
+                "서버 내부 오류가 발생했습니다. 잠시 후 다시 시도해주세요.",
+                e.getMessage()
+        );
+        return ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR).body(errorResponse);
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/exception/PostNotFoundException.java b/src/main/java/com/example/springbootassignment/exception/PostNotFoundException.java
new file mode 100644
index 0000000..f4a2932
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/exception/PostNotFoundException.java
@@ -0,0 +1,8 @@
+package com.example.springbootassignment.exception;
+
+public class PostNotFoundException extends RuntimeException {
+
+    public PostNotFoundException(Long postId) {
+        super("존재하지 않는 게시글입니다. id: " + postId);
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/exception/UnauthorizedException.java b/src/main/java/com/example/springbootassignment/exception/UnauthorizedException.java
new file mode 100644
index 0000000..d00afcf
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/exception/UnauthorizedException.java
@@ -0,0 +1,7 @@
+package com.example.springbootassignment.exception;
+
+public class UnauthorizedException extends RuntimeException {
+    public UnauthorizedException(String message) {
+        super(message);
+    }
+}
diff --git a/src/main/java/com/example/springbootassignment/service/PostService.java b/src/main/java/com/example/springbootassignment/service/PostService.java
new file mode 100644
index 0000000..12d6974
--- /dev/null
+++ b/src/main/java/com/example/springbootassignment/service/PostService.java
@@ -0,0 +1,80 @@
+package com.example.springbootassignment.service;
+
+import com.example.springbootassignment.domain.post.entity.Post;
+import com.example.springbootassignment.domain.post.entity.PostRepository;
+import com.example.springbootassignment.dto.PostCreateRequest;
+import com.example.springbootassignment.dto.PostListResponse;
+import com.example.springbootassignment.dto.PostResponse;
+import com.example.springbootassignment.dto.PostUpdateRequest;
+import com.example.springbootassignment.exception.PostNotFoundException;
+import org.springframework.data.domain.Page;
+import org.springframework.data.domain.PageRequest;
+import org.springframework.data.domain.Pageable;
+import org.springframework.data.domain.Sort;
+import org.springframework.stereotype.Service;
+
+@Service
+public class PostService {
+
+    private final PostRepository postRepository;
+
+    public PostService(PostRepository postRepository) {
+        this.postRepository = postRepository;
+    }
+
+    public PostListResponse getPostList(int page, int size, String sort, String order) {
+        int pageNumber = Math.max(0, page - 1);
+        Sort.Direction direction = "desc".equalsIgnoreCase(order) ? Sort.Direction.DESC : Sort.Direction.ASC;
+        Pageable pageable = PageRequest.of(pageNumber, size, Sort.by(direction, sort));
+        Page<Post> posts = postRepository.findAll(pageable);
+        return PostListResponse.from(posts);
+    }
+
+    public PostResponse getPostDetail(Long postId) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new PostNotFoundException(postId));
+        post.increaseViewCount();
+        postRepository.save(post);
+        return PostResponse.from(post);
+    }
+
+    public PostResponse createPost(PostCreateRequest request) {
+        if (request.getTitle() == null || request.getTitle().trim().isEmpty()) {
+            throw new IllegalArgumentException("제목은 필수입니다.");
+        }
+        if (request.getContent() == null || request.getContent().trim().isEmpty()) {
+            throw new IllegalArgumentException("내용은 필수입니다.");
+        }
+
+        Post post = new Post();
+        post.setTitle(request.getTitle());
+        post.setContent(request.getContent());
+
+        Post savedPost = postRepository.save(post);
+        return PostResponse.from(savedPost);
+    }
+
+    public PostResponse updatePost(Long postId, PostUpdateRequest request) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new PostNotFoundException(postId));
+
+        if (request.getTitle() == null || request.getTitle().trim().isEmpty()) {
+            throw new IllegalArgumentException("제목은 필수입니다.");
+        }
+        if (request.getContent() == null || request.getContent().trim().isEmpty()) {
+            throw new IllegalArgumentException("내용은 필수입니다.");
+        }
+
+        post.setTitle(request.getTitle());
+        post.setContent(request.getContent());
+
+        Post updatedPost = postRepository.save(post);
+        return PostResponse.from(updatedPost);
+    }
+
+    public void deletePost(Long postId) {
+        Post post = postRepository.findById(postId)
+                .orElseThrow(() -> new PostNotFoundException(postId));
+        postRepository.delete(post);
+    }
+}
diff --git a/src/main/resources/application.properties b/src/main/resources/application.properties
index e808fdd..6f8e689 100644
--- a/src/main/resources/application.properties
+++ b/src/main/resources/application.properties
@@ -4,6 +4,6 @@ spring.datasource.username=root
 spring.datasource.password=
 spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
 
-spring.jpa.hibernate.ddl-auto=update
+spring.jpa.hibernate.ddl-auto=create-drop
 spring.jpa.show-sql=true
-spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect
\ No newline at end of file
+spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQLDialect
diff --git a/test.http b/test.http
index 4e99134..5f0729a 100644
--- a/test.http
+++ b/test.http
@@ -4,4 +4,22 @@ Content-Type: application/json
 
 {
   "text": "hello"
-}
\ No newline at end of file
+}
+### POST - 게시글 작성
+POST http://localhost:8080/posts
+Content-Type: application/json
+
+{
+  "title": "첫 번째 게시글",
+  "content": "테스트 내용입니다"
+}
+### PUT - 게시글 수정
+PUT http://localhost:8080/posts/1
+Content-Type: application/json
+
+{
+  "title": "수정된 제목",
+  "content": "수정된 내용입니다"
+}
+### DELETE - 게시글 삭제
+DELETE http://localhost:8080/posts/1