diff --git a/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectApi.java b/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectApi.java
index cb88c7df..c203b251 100644
--- a/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectApi.java
+++ b/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectApi.java
@@ -1,6 +1,12 @@
 package org.layer.domain.retrospect.controller;
 
 import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.headers.Header;
+import io.swagger.v3.oas.annotations.media.Content;
+import io.swagger.v3.oas.annotations.media.ExampleObject;
+import io.swagger.v3.oas.annotations.media.Schema;
+import io.swagger.v3.oas.annotations.responses.ApiResponse;
+import io.swagger.v3.oas.annotations.responses.ApiResponses;
 import io.swagger.v3.oas.annotations.tags.Tag;
 import jakarta.validation.Valid;
 
@@ -31,4 +37,24 @@ ResponseEntity<RetrospectListGetResponse> updateRetrospect(@PathVariable("spaceI
 	@Operation(summary = "회고 삭제", description = "특정 팀 스페이스에서 작성했던 회고를 삭제하는 기능입니다.")
 	ResponseEntity<RetrospectListGetResponse> deleteRetrospect(@PathVariable("spaceId") Long spaceId,
 		@PathVariable("retrospectId") Long retrospectId, @MemberId Long memberId);
+
+	@Operation(summary = "회고 마감", description = "특정 팀 스페이스에서 작성했던 회고를 마감하는 기능입니다. </br> Note: 스페이스 내 모든 인원이 작성해야 가능합니다.")
+	@ApiResponses({
+		@ApiResponse(responseCode = "200", description = "회고 마감 성공",
+			content = @Content(mediaType = "application/json")),
+		@ApiResponse(responseCode = "400", description = "회고 마감 실패",
+			content = @Content(mediaType = "application/json", examples = {
+				@ExampleObject(name = "회고 마감 실패", value = """
+                                    {
+                                      "name": "NOT_COMPLETE_RETROSPECT_MEMBER",
+                                      "message": "회고를 작성하지 않은 팀원이 있습니다."
+                                    }
+                                    """
+				)
+			}))
+	})
+	ResponseEntity<Void> closeRetrospect(
+		@PathVariable("spaceId") Long spaceId,
+		@PathVariable("retrospectId") Long retrospectId,
+		@MemberId Long memberId);
 }
diff --git a/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectController.java b/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectController.java
index f3d334c3..28f5f351 100644
--- a/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectController.java
+++ b/layer-api/src/main/java/org/layer/domain/retrospect/controller/RetrospectController.java
@@ -75,4 +75,16 @@ public ResponseEntity<RetrospectListGetResponse> deleteRetrospect(@PathVariable(
 		return ResponseEntity.ok().build();
 	}
 
+	@Override
+	@PatchMapping("/{retrospectId}/close")
+	public ResponseEntity<Void> closeRetrospect(
+		@PathVariable("spaceId") Long spaceId,
+		@PathVariable("retrospectId") Long retrospectId,
+		@MemberId Long memberId) {
+
+		retrospectService.closeRetrospect(spaceId, retrospectId, memberId);
+
+		return ResponseEntity.ok().build();
+	}
+
 }
diff --git a/layer-api/src/main/java/org/layer/domain/retrospect/service/RetrospectService.java b/layer-api/src/main/java/org/layer/domain/retrospect/service/RetrospectService.java
index 66640108..a8080733 100644
--- a/layer-api/src/main/java/org/layer/domain/retrospect/service/RetrospectService.java
+++ b/layer-api/src/main/java/org/layer/domain/retrospect/service/RetrospectService.java
@@ -1,5 +1,7 @@
 package org.layer.domain.retrospect.service;
 
+import static org.layer.common.exception.RetrospectExceptionType.*;
+
 import lombok.RequiredArgsConstructor;
 
 import org.layer.domain.answer.entity.Answers;
@@ -18,6 +20,7 @@
 import org.layer.domain.retrospect.controller.dto.request.RetrospectUpdateRequest;
 import org.layer.domain.retrospect.entity.Retrospect;
 import org.layer.domain.retrospect.entity.RetrospectStatus;
+import org.layer.domain.retrospect.exception.RetrospectException;
 import org.layer.domain.retrospect.repository.RetrospectRepository;
 import org.layer.domain.retrospect.service.dto.response.RetrospectGetServiceResponse;
 import org.layer.domain.retrospect.service.dto.response.RetrospectListGetServiceResponse;
@@ -27,6 +30,7 @@
 import org.layer.domain.space.repository.SpaceRepository;
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
+import org.springframework.web.bind.annotation.PathVariable;
 
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -149,4 +153,26 @@ public void deleteRetrospect(Long spaceId, Long retrospectId, Long memberId) {
 		Retrospect retrospect = retrospectRepository.findByIdOrThrow(retrospectId);
 		retrospectRepository.delete(retrospect);
 	}
+
+	@Transactional
+	public void closeRetrospect(Long spaceId, Long retrospectId, Long memberId) {
+		// 해당 스페이스 팀원인지 검증
+		Team team = new Team(memberSpaceRelationRepository.findAllBySpaceId(spaceId));
+		team.validateTeamMembership(memberId);
+
+		// 팀장인지 검증
+		Space space = spaceRepository.findByIdOrThrow(spaceId);
+		space.isLeaderSpace(memberId);
+
+		// 팀원 모두 회고를 작성했는지 검증
+		Retrospect retrospect = retrospectRepository.findByIdOrThrow(retrospectId);
+
+		Answers answers = new Answers(answerRepository.findAllByRetrospectId(retrospectId));
+
+		if (answers.getWriteCount() != team.getTeamMemberCount()) {
+			throw new RetrospectException(NOT_COMPLETE_RETROSPECT_MEMBER);
+		}
+
+		retrospect.updateRetrospectStatus(RetrospectStatus.DONE);
+	}
 }
diff --git a/layer-common/src/main/java/org/layer/common/exception/RetrospectExceptionType.java b/layer-common/src/main/java/org/layer/common/exception/RetrospectExceptionType.java
index 6f85cea0..8d60b615 100644
--- a/layer-common/src/main/java/org/layer/common/exception/RetrospectExceptionType.java
+++ b/layer-common/src/main/java/org/layer/common/exception/RetrospectExceptionType.java
@@ -7,6 +7,7 @@
 @RequiredArgsConstructor
 public enum RetrospectExceptionType implements ExceptionType {
 	INVALID_DEADLINE(HttpStatus.BAD_REQUEST, "회고 마감기한이 유효하지 않습니다."),
+	NOT_COMPLETE_RETROSPECT_MEMBER(HttpStatus.BAD_REQUEST, "회고를 작성하지 않은 팀원이 있습니다."),
 	DEADLINE_PASSED(HttpStatus.BAD_REQUEST, "회고 마감기한이 지났습니다."),
 	DEADLINE_NOT_PASSED(HttpStatus.BAD_REQUEST, "회고가 마감되지 않았습니다."),
 	NOT_PROCEEDING_RETROSPECT(HttpStatus.BAD_REQUEST, "진행중인 회고가 아닙니다."),
diff --git a/layer-domain/src/main/java/org/layer/domain/retrospect/entity/Retrospect.java b/layer-domain/src/main/java/org/layer/domain/retrospect/entity/Retrospect.java
index c14a4c53..0bac6f16 100644
--- a/layer-domain/src/main/java/org/layer/domain/retrospect/entity/Retrospect.java
+++ b/layer-domain/src/main/java/org/layer/domain/retrospect/entity/Retrospect.java
@@ -82,4 +82,10 @@ public void updateRetrospect(String title, String introduction, LocalDateTime de
 		this.introduction = introduction;
 		this.deadline = deadline;
 	}
+
+	public void updateRetrospectStatus(RetrospectStatus retrospectStatus){
+		isProceedingRetrospect();
+
+		this.retrospectStatus = retrospectStatus;
+	}
 }
diff --git a/layer-domain/src/main/java/org/layer/domain/space/entity/Team.java b/layer-domain/src/main/java/org/layer/domain/space/entity/Team.java
index 580ea533..35b8b20c 100644
--- a/layer-domain/src/main/java/org/layer/domain/space/entity/Team.java
+++ b/layer-domain/src/main/java/org/layer/domain/space/entity/Team.java
@@ -19,7 +19,7 @@ public void validateTeamMembership(Long memberId){
 			.orElseThrow(() -> new MemberSpaceRelationException(NOT_FOUND_MEMBER_SPACE_RELATION));
 	}
 
-	public int getTeamMemberCount(){
+	public long getTeamMemberCount(){
 		return memberSpaceRelations.size();
 	}
 }