diff --git a/src/main/java/com/campick/server/api/chat/controller/ChatController.java b/src/main/java/com/campick/server/api/chat/controller/ChatController.java
index ad73683..0590a19 100644
--- a/src/main/java/com/campick/server/api/chat/controller/ChatController.java
+++ b/src/main/java/com/campick/server/api/chat/controller/ChatController.java
@@ -36,6 +36,14 @@ public ResponseEntity<ApiResponse<ChatRoomResDto>> getChatRoom(@PathVariable Lon
         return ApiResponse.success(SuccessStatus.SEND_LOAD_CHATROOM, chatService.getChatRoom(chatRoomId));
     }
 
+    @PatchMapping("/{chatRoomId}")
+    public ResponseEntity<ApiResponse<Void>> readChatRoom(@PathVariable Long chatRoomId,
+                                                          @AuthenticationPrincipal SecurityMember securityMember) {
+        Long memberId =  securityMember.getId();
+        chatService.readChatRoom(chatRoomId, memberId);
+        return ApiResponse.success_only(SuccessStatus.READ_CHAT_SUCCESS);
+    }
+
     @GetMapping("/my")
     public ResponseEntity<ApiResponse<MyChatResDto>> getMyChatRoom(@AuthenticationPrincipal SecurityMember securityMember) {
         Long memberId = securityMember.getId();
@@ -55,6 +63,5 @@ public ResponseEntity<ApiResponse<Void>> completeChat(@PathVariable Long chatRoo
         Long memberId = securityMember.getId();
         chatService.completeChat(chatRoomId, memberId);
         return ApiResponse.success_only(SuccessStatus.COMPLETE_CHAT);
-
     }
 }
diff --git a/src/main/java/com/campick/server/api/chat/repository/ChatMessageRepository.java b/src/main/java/com/campick/server/api/chat/repository/ChatMessageRepository.java
index 65db83b..e7ffc2f 100644
--- a/src/main/java/com/campick/server/api/chat/repository/ChatMessageRepository.java
+++ b/src/main/java/com/campick/server/api/chat/repository/ChatMessageRepository.java
@@ -2,6 +2,7 @@
 
 import com.campick.server.api.chat.entity.ChatMessage;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.data.jpa.repository.Modifying;
 import org.springframework.data.jpa.repository.Query;
 import org.springframework.data.repository.query.Param;
 
@@ -14,6 +15,16 @@ public interface ChatMessageRepository extends JpaRepository<ChatMessage, Long>
             "ORDER BY cm.createdAt ASC")
     List<ChatMessage> findMessagesByChatRoomId(@Param("chatRoomId") Long chatRoomId);
 
+    @Modifying
+    @Query("UPDATE ChatMessage m " +
+            "SET m.isRead = true " +
+            "WHERE m.chatRoom.id = :chatRoomId " +
+            "AND m.member.id <> :memberId " +
+            "AND m.isRead = false")
+    Integer markMessagesAsRead(@Param("chatRoomId") Long chatRoomId,
+                           @Param("memberId") Long memberId);
+
+
     @Query("SELECT m FROM ChatMessage m " +
             "WHERE m.chatRoom.id = :chatRoomId " +
             "ORDER BY m.createdAt DESC LIMIT 1")
diff --git a/src/main/java/com/campick/server/api/chat/repository/ChatRoomRepository.java b/src/main/java/com/campick/server/api/chat/repository/ChatRoomRepository.java
index 7dade22..3ba29d2 100644
--- a/src/main/java/com/campick/server/api/chat/repository/ChatRoomRepository.java
+++ b/src/main/java/com/campick/server/api/chat/repository/ChatRoomRepository.java
@@ -23,7 +23,9 @@ public interface ChatRoomRepository extends JpaRepository<ChatRoom, Long> {
             "JOIN FETCH cr.product p " +
             "JOIN FETCH cr.seller s " +
             "JOIN FETCH cr.buyer b " +
-            "WHERE s.id = :memberId OR b.id = :memberId")
+            "WHERE (s.id = :memberId OR b.id = :memberId) " +
+            "AND ((s.id = :memberId AND cr.isSellerOut = false) " +
+            "     OR (b.id = :memberId AND cr.isBuyerOut = false))")
     List<ChatRoom> findAllByMemberId(@Param("memberId") Long memberId);
 
     Optional<ChatRoom> findByProductAndSellerAndBuyer(Product product, Member seller, Member buyer);
diff --git a/src/main/java/com/campick/server/api/chat/service/ChatService.java b/src/main/java/com/campick/server/api/chat/service/ChatService.java
index 2f82c70..0489fff 100644
--- a/src/main/java/com/campick/server/api/chat/service/ChatService.java
+++ b/src/main/java/com/campick/server/api/chat/service/ChatService.java
@@ -117,6 +117,10 @@ public ChatRoomResDto getChatRoom(Long chatRoomId) {
         return convertToChatRoomResDto(chatRoom, chatMessages);
     }
 
+    public void readChatRoom(Long chatRoomId, Long memberId) {
+        Integer readMessageCount = chatMessageRepository.markMessagesAsRead(chatRoomId, memberId);
+    }
+
     public MyChatResDto getMyChatRooms(Long memberId) {
         List<ChatRoom> myChatRooms = chatRoomRepository.findAllByMemberId(memberId);
         List<ChatListDto> chatListDtos = myChatRooms.stream().map(
diff --git a/src/main/java/com/campick/server/common/response/SuccessStatus.java b/src/main/java/com/campick/server/common/response/SuccessStatus.java
index a0ceacc..013bef0 100644
--- a/src/main/java/com/campick/server/common/response/SuccessStatus.java
+++ b/src/main/java/com/campick/server/common/response/SuccessStatus.java
@@ -69,6 +69,7 @@ public enum SuccessStatus {
     SEND_TOTAL_UNREAD_MSG(HttpStatus.OK, "총 안 읽은 메시지 수 조회 성공"),
     COMPLETE_CHAT(HttpStatus.OK, "채팅방 종료 완료"),
     UPLOAD_CHAT_IMAGE_SUCCESS(HttpStatus.OK, "채팅방 내 이미지 업로드 성공"),
+    READ_CHAT_SUCCESS(HttpStatus.OK, "채팅방 읽음 성공"),
 
 
     /**