diff --git a/src/main/java/com/back/matchduo/domain/party/dto/PartyDto.java b/src/main/java/com/back/matchduo/domain/party/dto/PartyDto.java
deleted file mode 100644
index 39d9bbc..0000000
--- a/src/main/java/com/back/matchduo/domain/party/dto/PartyDto.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package com.back.matchduo.domain.party.dto;
-
-public class PartyDto {
-}
-
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/request/PartyCloseRequest.java b/src/main/java/com/back/matchduo/domain/party/dto/request/PartyCloseRequest.java
new file mode 100644
index 0000000..38a4b43
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/request/PartyCloseRequest.java
@@ -0,0 +1,5 @@
+package com.back.matchduo.domain.party.dto.request;
+
+public record PartyCloseRequest(
+        Long partyId
+) {}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/request/PartyMemberAddRequest.java b/src/main/java/com/back/matchduo/domain/party/dto/request/PartyMemberAddRequest.java
new file mode 100644
index 0000000..8aa71f8
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/request/PartyMemberAddRequest.java
@@ -0,0 +1,10 @@
+package com.back.matchduo.domain.party.dto.request;
+
+import jakarta.validation.constraints.NotEmpty;
+
+import java.util.List;
+
+public record PartyMemberAddRequest(
+        @NotEmpty(message = "추가할 유저를 최소 1명 이상 선택해주세요.")
+        List<Long> targetUserIds // 다인파티 확정성 고려하여 List로 받음
+) {}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/MyPartyListResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/MyPartyListResponse.java
new file mode 100644
index 0000000..10294c1
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/MyPartyListResponse.java
@@ -0,0 +1,33 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import com.back.matchduo.domain.party.entity.PartyMemberRole;
+import com.back.matchduo.domain.party.entity.PartyStatus;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+public record MyPartyListResponse(
+        List<MyPartyDto> parties
+) {
+    public record MyPartyDto(
+            Long partyId,
+            Long postId,
+            String postTitle,
+            String gameMode,
+            PartyStatus status,
+            PartyMemberRole myRole,
+            LocalDateTime joinedAt
+    ) {
+        public static MyPartyDto of(Long partyId, Long postId, String postTitle, String gameMode, PartyStatus status, PartyMemberRole myRole, LocalDateTime joinedAt) {
+            return new MyPartyDto(
+                    partyId,
+                    postId,
+                    postTitle,
+                    gameMode,
+                    status,
+                    myRole,
+                    joinedAt
+            );
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/PartyByPostResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyByPostResponse.java
new file mode 100644
index 0000000..4e8ea45
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyByPostResponse.java
@@ -0,0 +1,30 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import com.back.matchduo.domain.party.entity.PartyMemberRole;
+import com.back.matchduo.domain.party.entity.PartyStatus;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+public record PartyByPostResponse(
+        Long partyId,
+        Long postId,
+        PartyStatus status,
+        int currentCount,
+        int maxCount,
+        LocalDateTime createdAt,
+        boolean isJoined,
+        List<PartyMemberDto> members
+) {
+    public record PartyMemberDto(
+            Long partyMemberId,
+            Long userId,
+            String nickname,
+            String profileImage,
+            PartyMemberRole role
+    ) {
+        public static PartyMemberDto of(Long partyMemberId, Long userId, String nickname, String profileImage, PartyMemberRole role) {
+            return new PartyMemberDto(partyMemberId, userId, nickname, profileImage, role);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/PartyCloseResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyCloseResponse.java
new file mode 100644
index 0000000..2b50f50
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyCloseResponse.java
@@ -0,0 +1,9 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import java.time.LocalDateTime;
+
+public record PartyCloseResponse(
+        Long partyId,
+        String status, // "CLOSED"
+        LocalDateTime closedAt
+) {}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberAddResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberAddResponse.java
new file mode 100644
index 0000000..421e8a0
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberAddResponse.java
@@ -0,0 +1,29 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import com.back.matchduo.domain.party.entity.PartyMember;
+import com.back.matchduo.domain.party.entity.PartyMemberRole;
+import com.back.matchduo.domain.party.entity.PartyMemberState;
+
+import java.time.LocalDateTime;
+
+public record PartyMemberAddResponse(
+        Long partyMemberId,
+        Long userId,
+        String nickname,
+        String profileImage,
+        PartyMemberRole role,// LEADER / MEMBER
+        PartyMemberState state,// JOINED
+        LocalDateTime joinedAt
+) {
+    public static PartyMemberAddResponse of(PartyMember member, String nickname, String profileImage) {
+        return new PartyMemberAddResponse(
+                member.getId(),
+                member.getUserId(),
+                nickname,
+                profileImage,
+                member.getRole(),
+                member.getState(),
+                member.getJoinedAt()
+        );
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberListResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberListResponse.java
new file mode 100644
index 0000000..add05f0
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberListResponse.java
@@ -0,0 +1,33 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import com.back.matchduo.domain.party.entity.PartyMemberRole;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+public record PartyMemberListResponse(
+        Long partyId,
+        int currentCount,
+        int maxCount,
+        List<PartyMemberDto> members
+) {
+    public record PartyMemberDto(
+            Long partyMemberId,
+            Long userId,
+            String nickname,
+            String profileImage,
+            PartyMemberRole role, // LEADER / MEMBER
+            LocalDateTime joinedAt
+    ) {
+        public static PartyMemberDto of(Long partyMemberId, Long userId, PartyMemberRole role, LocalDateTime joinedAt, String nickname, String profileImage) {
+            return new PartyMemberDto(
+                    partyMemberId,
+                    userId,
+                    nickname,
+                    profileImage,
+                    role,
+                    joinedAt
+            );
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberRemoveResponse.java b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberRemoveResponse.java
new file mode 100644
index 0000000..083156c
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/dto/response/PartyMemberRemoveResponse.java
@@ -0,0 +1,20 @@
+package com.back.matchduo.domain.party.dto.response;
+
+import com.back.matchduo.domain.party.entity.PartyMember;
+import java.time.LocalDateTime;
+
+public record PartyMemberRemoveResponse(
+        Long partyMemberId,
+        Long userId,
+        String state,// "LEFT"
+        LocalDateTime leftAt
+) {
+    public static PartyMemberRemoveResponse from(PartyMember member) {
+        return new PartyMemberRemoveResponse(
+                member.getId(),
+                member.getUserId(),
+                member.getState().name(),
+                member.getLeftAt()
+        );
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/entity/Party.java b/src/main/java/com/back/matchduo/domain/party/entity/Party.java
index 7687a58..2a4acc2 100644
--- a/src/main/java/com/back/matchduo/domain/party/entity/Party.java
+++ b/src/main/java/com/back/matchduo/domain/party/entity/Party.java
@@ -1,10 +1,67 @@
 package com.back.matchduo.domain.party.entity;
 
 import jakarta.persistence.*;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.time.LocalDateTime;
 
 @Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Table(name = "party")
 public class Party {
+
     @Id
     @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "party_id")
     private Long id;
+
+    @Column(name = "post_id", nullable = false)
+    private Long postId;
+
+    @Column(name = "leader_id", nullable = false)
+    private Long leaderId;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private PartyStatus status;
+
+    @Column(name = "created_at", nullable = false)
+    private LocalDateTime createdAt;
+
+    // 자동 파티완료 된 경우
+    @Column(name = "expires_at", nullable = false)
+    private LocalDateTime expiresAt;
+
+    // 수동 파티완료, 자동 파티완료 된 경우의 시간
+    @Column(name = "closed_at")
+    private LocalDateTime closedAt;
+
+
+    public Party(Long postId, Long leaderId) {
+        this.postId = postId;
+        this.leaderId = leaderId;
+        this.status = PartyStatus.ACTIVE;
+        this.createdAt = LocalDateTime.now();
+        this.expiresAt = this.createdAt.plusHours(6);
+        }
+
+
+    // 파티장이 수동 파티완료 처리
+    public void closeParty() {
+        if (this.status == PartyStatus.ACTIVE) {
+            this.status = PartyStatus.CLOSED;
+            this.closedAt = LocalDateTime.now(); // 현재 시간 기록
+        }
+    }
+
+    // 스케줄러가 자동 파티완료 처리
+    public void expireParty() {
+        if (this.status == PartyStatus.ACTIVE) {
+            this.status = PartyStatus.CLOSED;
+            this.closedAt = this.expiresAt; // 만료 예정 시간이 곧 종료 시간
+        }
+    }
 }
diff --git a/src/main/java/com/back/matchduo/domain/party/entity/PartyMember.java b/src/main/java/com/back/matchduo/domain/party/entity/PartyMember.java
new file mode 100644
index 0000000..7d60513
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/entity/PartyMember.java
@@ -0,0 +1,72 @@
+package com.back.matchduo.domain.party.entity;
+
+import jakarta.persistence.*;
+import lombok.AccessLevel;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+import java.time.LocalDateTime;
+
+@Entity
+@Getter
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@Table(
+        // 파티 중복 참여 방지 unique
+        name = "party_member",
+        uniqueConstraints = {
+                @UniqueConstraint(
+                        name = "uk_party_member_user",
+                        columnNames = {"party_id", "user_id"}
+                )
+        }
+)
+public class PartyMember {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    @Column(name = "party_member_id")
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "party_id", nullable = false)
+    private Party party;
+
+    @Column(name = "user_id", nullable = false)
+    private Long userId;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private PartyMemberRole role; // LEADER, MEMBER
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private PartyMemberState state; // JOINED, LEFT
+
+    @Column(name = "joined_at", nullable = false)
+    private LocalDateTime joinedAt;
+
+    @Column(name = "left_at")
+    private LocalDateTime leftAt;
+
+
+    public PartyMember(Party party, Long userId, PartyMemberRole role) {
+        this.party = party;
+        this.userId = userId;
+        this.role = role;
+        this.state = PartyMemberState.JOINED;
+        this.joinedAt = LocalDateTime.now();
+    }
+
+
+    public void leaveParty() {
+        this.state = PartyMemberState.LEFT;
+        this.leftAt = LocalDateTime.now();
+    }
+
+    // 나갔던 유저가 다시 들어올 때 사용
+    public void rejoinParty() {
+        this.state = PartyMemberState.JOINED;
+        this.joinedAt = LocalDateTime.now();
+        this.leftAt = null;
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberRole.java b/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberRole.java
new file mode 100644
index 0000000..b68da92
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberRole.java
@@ -0,0 +1,6 @@
+package com.back.matchduo.domain.party.entity;
+
+public enum PartyMemberRole {
+     LEADER, // 파티장
+     MEMBER // 파티원
+ }
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberState.java b/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberState.java
new file mode 100644
index 0000000..403fb68
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/entity/PartyMemberState.java
@@ -0,0 +1,6 @@
+package com.back.matchduo.domain.party.entity;
+
+public enum PartyMemberState {
+    JOINED, // 참여 중
+    LEFT,   // 나감 (탈퇴/강퇴)
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/entity/PartyStatus.java b/src/main/java/com/back/matchduo/domain/party/entity/PartyStatus.java
new file mode 100644
index 0000000..a1c71d0
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/entity/PartyStatus.java
@@ -0,0 +1,6 @@
+package com.back.matchduo.domain.party.entity;
+
+public enum PartyStatus {
+     ACTIVE, // 모집완료 시
+    CLOSED // 모집중 , 게임완료(수동, 6시간 자동 포함)
+}
diff --git a/src/main/java/com/back/matchduo/domain/party/repository/PartyMemberRepository.java b/src/main/java/com/back/matchduo/domain/party/repository/PartyMemberRepository.java
new file mode 100644
index 0000000..9f493c6
--- /dev/null
+++ b/src/main/java/com/back/matchduo/domain/party/repository/PartyMemberRepository.java
@@ -0,0 +1,22 @@
+package com.back.matchduo.domain.party.repository;
+
+import com.back.matchduo.domain.party.entity.PartyMember;
+import org.springframework.data.jpa.repository.JpaRepository;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface PartyMemberRepository extends JpaRepository<PartyMember, Long> {
+
+    // 1. 특정 파티의 멤버 목록 조회 (가입된 상태만 가져오거나, 전체 다 가져오거나)
+    List<PartyMember> findByPartyId(Long partyId);
+
+    // 2. 내가 참여한 파티 목록 조회
+    List<PartyMember> findByUserId(Long userId);
+
+    // 3. 이미 참여했는지 확인 (중복 참여 방지)
+    boolean existsByPartyIdAndUserId(Long partyId, Long userId);
+
+    // 4. 특정 파티에서 내 멤버 정보 찾기
+    Optional<PartyMember> findByPartyIdAndUserId(Long partyId, Long userId);
+}
\ No newline at end of file
diff --git a/src/main/java/com/back/matchduo/domain/party/repository/PartyRepository.java b/src/main/java/com/back/matchduo/domain/party/repository/PartyRepository.java
index d05021d..ca2257e 100644
--- a/src/main/java/com/back/matchduo/domain/party/repository/PartyRepository.java
+++ b/src/main/java/com/back/matchduo/domain/party/repository/PartyRepository.java
@@ -1,7 +1,20 @@
 package com.back.matchduo.domain.party.repository;
 
 import com.back.matchduo.domain.party.entity.Party;
+import com.back.matchduo.domain.party.entity.PartyStatus;
 import org.springframework.data.jpa.repository.JpaRepository;
 
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Optional;
+
 public interface PartyRepository extends JpaRepository<Party, Long> {
+
+    // 1. 모집글 ID로 파티 조회
+    // 용도: GET /api/v1/posts/{postId}/party (모집글 눌렀을 때 파티 정보 띄우기)
+    Optional<Party> findByPostId(Long postId);
+
+    // 2. 만료 시간이 지났고, 상태가 ACTIVE인 파티 조회
+    // 용도: 스케줄러가 6시간 지난 파티를 찾아서 자동으로 닫을 때 사용
+    List<Party> findByStatusAndExpiresAtBefore(PartyStatus status, LocalDateTime now);
 }