diff --git a/src/main/java/kr/re/etri/autoflow/controllers/AuthController.java b/src/main/java/kr/re/etri/autoflow/controllers/AuthController.java
index 15ceb85..3d7fec0 100644
--- a/src/main/java/kr/re/etri/autoflow/controllers/AuthController.java
+++ b/src/main/java/kr/re/etri/autoflow/controllers/AuthController.java
@@ -5,8 +5,10 @@ import java.util.stream.Collectors;
 
 import io.swagger.v3.oas.annotations.Parameter;
 import jakarta.servlet.http.HttpServletRequest;
+import jakarta.transaction.Transactional;
 import jakarta.validation.Valid;
 
+import kr.re.etri.autoflow.repository.UserProjectMapRepository;
 import kr.re.etri.autoflow.service.AuthService;
 import kr.re.etri.autoflow.service.UserService;
 import lombok.RequiredArgsConstructor;
@@ -61,6 +63,7 @@ public class AuthController {
   RefreshTokenService refreshTokenService;
 
   private final AuthService authService;
+  private final UserProjectMapRepository userProjectMapRepository;
   private final UserService userService;
 
     @Operation(summary = "로그인", description = "사용자 인증 후 JWT 및 리프레시 토큰 쿠키를 반환합니다.")
@@ -75,11 +78,11 @@ public class AuthController {
     }
 
     @Operation(summary = "회원가입", description = "새로운 사용자를 등록합니다.")
-  @ApiResponses({
+    @ApiResponses({
           @ApiResponse(responseCode = "200", description = "회원가입 성공"),
           @ApiResponse(responseCode = "400", description = "중복된 사용자명 또는 이메일")
-  })
-  @PostMapping("/signup")
+    })
+    @PostMapping("/signup")
   public ResponseEntity<?> registerUser(@Valid @RequestBody SignupRequest signUpRequest) {
     if (userRepository.existsByUsername(signUpRequest.getUsername())) {
       return ResponseEntity.badRequest().body(new MessageResponse(false,"오류: 이미 사용 중인 사용자 이름입니다."));
@@ -244,13 +247,22 @@ public class AuthController {
             @ApiResponse(responseCode = "404", description = "해당 ID의 사용자를 찾을 수 없음")
     })
     @DeleteMapping("/users/{id}")
+    @Transactional
     public ResponseEntity<MessageResponse> deleteUser(
             @Parameter(description = "사용자 ID", example = "1") @PathVariable Long id) {
 
         return userRepository.findById(id).map(user -> {
-            refreshTokenService.deleteByUserId(user.getId()); // 토큰 삭제
+            // 1. 리프레시 토큰 삭제
+            refreshTokenService.deleteByUserId(user.getId());
+
+            // 2. 사용자-프로젝트 맵 삭제
+            userProjectMapRepository.deleteAllByUserId(user.getId());
+
+            // 3. 사용자 삭제
             userRepository.delete(user);
+
             return ResponseEntity.ok(new MessageResponse(true, "사용자가 삭제되었습니다."));
         }).orElse(ResponseEntity.notFound().build());
     }
+
 }
diff --git a/src/main/java/kr/re/etri/autoflow/repository/UserProjectMapRepository.java b/src/main/java/kr/re/etri/autoflow/repository/UserProjectMapRepository.java
index 4bd4fec..66432e0 100644
--- a/src/main/java/kr/re/etri/autoflow/repository/UserProjectMapRepository.java
+++ b/src/main/java/kr/re/etri/autoflow/repository/UserProjectMapRepository.java
@@ -13,7 +13,9 @@ public interface UserProjectMapRepository extends JpaRepository<UserProjectMapEn
 
     Optional<UserProjectMapEntity> findByProjectAndUser(ProjectEntity project, User user);
 
-    List<UserProjectMapEntity> findAllByProject(ProjectEntity project);
-
     List<UserProjectMapEntity> findAllByUserId(Long userId);
+
+    void deleteAllByUserId(Long id);
+
+    void deleteAllByProjectId(Long id);
 }
diff --git a/src/main/java/kr/re/etri/autoflow/service/ProjectService.java b/src/main/java/kr/re/etri/autoflow/service/ProjectService.java
index c4c0d13..a340cf7 100644
--- a/src/main/java/kr/re/etri/autoflow/service/ProjectService.java
+++ b/src/main/java/kr/re/etri/autoflow/service/ProjectService.java
@@ -99,7 +99,13 @@ public class ProjectService {
         if (!projectRepository.existsById(id)) {
             return false;
         }
+
+        // 연관 레코드 삭제
+        userProjectMapRepository.deleteAllByProjectId(id);
+
+        // 프로젝트 삭제
         projectRepository.deleteById(id);
         return true;
     }
+
 }