diff --git a/src/app.module.ts b/src/app.module.ts
index 0ece03d..ef756a0 100644
--- a/src/app.module.ts
+++ b/src/app.module.ts
@@ -9,6 +9,7 @@ import { AuthModule } from './auth/auth.module';
 import { OrganModule } from './organ/organ.module';
 import { ComplaintModule } from './complaint/complaint.module';
 import { AttachmentModule } from './attachment/attachment.module';
+import { ReplyModule } from './reply/reply.module';
 
 @Module({
   imports: [
@@ -22,7 +23,8 @@ import { AttachmentModule } from './attachment/attachment.module';
     AuthModule,
     OrganModule,
     ComplaintModule,
-    AttachmentModule
+    AttachmentModule,
+    ReplyModule
   ],
 })
 export class AppModule {}
diff --git a/src/attachment/entities/attachment.entity.ts b/src/attachment/entities/attachment.entity.ts
index 7df7e46..5120678 100644
--- a/src/attachment/entities/attachment.entity.ts
+++ b/src/attachment/entities/attachment.entity.ts
@@ -2,6 +2,7 @@ import { BaseEntity } from "src/common/entities/base.entity";
 import { Column, Entity, OneToOne } from "typeorm";
 import { AttachmentType } from "../enums/attachment-type.enum";
 import { ComplaintAttachment } from "src/complaint/entities/complaint-attachment.entity";
+import { ReplyAttachment } from "src/reply/entities/reply-attachment.entity";
 
 @Entity('attachments')
 export class Attachment extends BaseEntity{
@@ -24,4 +25,7 @@ export class Attachment extends BaseEntity{
 
     @OneToOne(() => ComplaintAttachment, (ca) => ca.attachment)
     complaint: ComplaintAttachment;
+
+    @OneToOne(() => ReplyAttachment, (ra) => ra.attachment)
+    reply: ReplyAttachment;
 }
diff --git a/src/common/enums/messages.enum.ts b/src/common/enums/messages.enum.ts
index b11c09e..63147cf 100644
--- a/src/common/enums/messages.enum.ts
+++ b/src/common/enums/messages.enum.ts
@@ -30,4 +30,8 @@ export enum ComplaintMessages {
 
 export enum AttachmentMessages {
     ATTACHMENT_NOT_FOUND = 'ضمیمه مورد نظر پیدا نشد!'
+}
+
+export enum ReplyMessages {
+    REPLY_NOT_FOUND = 'پاسخ مورد نظر پیدا نشد!'
 }
\ No newline at end of file
diff --git a/src/complaint/entities/complaint.entity.ts b/src/complaint/entities/complaint.entity.ts
index 8ca0315..228c3fd 100644
--- a/src/complaint/entities/complaint.entity.ts
+++ b/src/complaint/entities/complaint.entity.ts
@@ -4,6 +4,7 @@ import { User } from 'src/users/entities/user.entity';
 import { Organ } from 'src/organ/entities/organ.entity';
 import { BaseEntity } from 'src/common/entities/base.entity';
 import { ComplaintAttachment } from './complaint-attachment.entity';
+import { Reply } from 'src/reply/entities/reply.entity';
 
 @Entity('complaints')
 export class Complaint extends BaseEntity {
@@ -45,4 +46,7 @@ export class Complaint extends BaseEntity {
 
   @OneToMany(() => ComplaintAttachment, (ca) => ca.complaint)
   attachments: ComplaintAttachment[];
+
+  @OneToMany(() => Reply, (reply) => reply.complaint)
+  messages: Reply[];
 }
diff --git a/src/reply/dto/create-reply.dto.ts b/src/reply/dto/create-reply.dto.ts
new file mode 100644
index 0000000..1d73c38
--- /dev/null
+++ b/src/reply/dto/create-reply.dto.ts
@@ -0,0 +1,32 @@
+import { ApiProperty } from "@nestjs/swagger";
+import { IsNotEmpty, IsString, IsUUID } from "class-validator";
+
+export class CreateReplyDto {
+    @ApiProperty({
+        description: 'text content of the reply'
+    })
+    @IsString()
+    @IsNotEmpty()
+    content: string;
+
+    @ApiProperty({
+        description: 'Id of the sender user'
+    })
+    @IsNotEmpty()
+    @IsUUID()
+    senderId: string;
+
+    @ApiProperty({
+        description: 'Id of the receiver user'
+    })
+    @IsNotEmpty()
+    @IsUUID()
+    receiverId: string;
+
+    @ApiProperty({
+        description: 'Id of the Complaint'
+    })
+    @IsNotEmpty()
+    @IsUUID()
+    complaintId: string;
+}
diff --git a/src/reply/dto/update-reply.dto.ts b/src/reply/dto/update-reply.dto.ts
new file mode 100644
index 0000000..7ace067
--- /dev/null
+++ b/src/reply/dto/update-reply.dto.ts
@@ -0,0 +1,4 @@
+import { PartialType } from '@nestjs/swagger';
+import { CreateReplyDto } from './create-reply.dto';
+
+export class UpdateReplyDto extends PartialType(CreateReplyDto) {}
diff --git a/src/reply/entities/reply-attachment.entity.ts b/src/reply/entities/reply-attachment.entity.ts
new file mode 100644
index 0000000..43a9b91
--- /dev/null
+++ b/src/reply/entities/reply-attachment.entity.ts
@@ -0,0 +1,19 @@
+import { BaseEntity } from "src/common/entities/base.entity";
+import { Column, Entity, JoinColumn, ManyToOne, OneToOne } from "typeorm";
+import { Reply } from "./reply.entity";
+import { Attachment } from "src/attachment/entities/attachment.entity";
+
+@Entity('reply_attachments')
+export class ReplyAttachment extends BaseEntity {
+    @ManyToOne(() => Reply, (rp) => rp.attachments, {
+        onDelete: 'CASCADE'
+    })
+    reply: Reply;
+
+    @OneToOne(() => Attachment, (attch) => attch.reply, {
+        cascade: true,
+        onDelete: 'CASCADE'
+    })
+    @JoinColumn()
+    attachment: Attachment;
+}
\ No newline at end of file
diff --git a/src/reply/entities/reply.entity.ts b/src/reply/entities/reply.entity.ts
new file mode 100644
index 0000000..9c362ce
--- /dev/null
+++ b/src/reply/entities/reply.entity.ts
@@ -0,0 +1,26 @@
+import { Attachment } from "src/attachment/entities/attachment.entity";
+import { BaseEntity } from "src/common/entities/base.entity";
+import { Complaint } from "src/complaint/entities/complaint.entity";
+import { User } from "src/users/entities/user.entity";
+import { Column, Entity, ManyToOne, OneToMany } from "typeorm";
+import { ReplyAttachment } from "./reply-attachment.entity";
+
+@Entity('replies')
+export class Reply extends BaseEntity {
+    @Column({
+        type: 'text'
+    })
+    content: string; // the text or message written.
+
+    @ManyToOne(() => User)
+    sender: User;
+
+    @ManyToOne(()  => User)
+    receiver: User;
+
+    @ManyToOne(() => Complaint, (complaint) => complaint.messages)
+    complaint: Complaint;
+
+    @OneToMany(() => ReplyAttachment, (ra) => ra.reply)
+    attachments: ReplyAttachment;
+}
diff --git a/src/reply/reply.controller.ts b/src/reply/reply.controller.ts
new file mode 100644
index 0000000..687547f
--- /dev/null
+++ b/src/reply/reply.controller.ts
@@ -0,0 +1,34 @@
+import { Controller, Get, Post, Body, Patch, Param, Delete } from '@nestjs/common';
+import { ReplyService } from './reply.service';
+import { CreateReplyDto } from './dto/create-reply.dto';
+import { UpdateReplyDto } from './dto/update-reply.dto';
+
+@Controller('reply')
+export class ReplyController {
+  constructor(private readonly replyService: ReplyService) {}
+
+  @Post()
+  create(@Body() createReplyDto: CreateReplyDto) {
+    return this.replyService.create(createReplyDto);
+  }
+
+  @Get()
+  findAll() {
+    return this.replyService.findAll();
+  }
+
+  @Get(':id')
+  findOne(@Param('id') id: string) {
+    return this.replyService.findOneOrFail(id);
+  }
+
+  @Patch(':id')
+  update(@Param('id') id: string, @Body() updateReplyDto: UpdateReplyDto) {
+    return this.replyService.update(id, updateReplyDto);
+  }
+
+  @Delete(':id')
+  remove(@Param('id') id: string) {
+    return this.replyService.remove(id);
+  }
+}
diff --git a/src/reply/reply.module.ts b/src/reply/reply.module.ts
new file mode 100644
index 0000000..5c884d4
--- /dev/null
+++ b/src/reply/reply.module.ts
@@ -0,0 +1,15 @@
+import { Module } from '@nestjs/common';
+import { ReplyService } from './reply.service';
+import { ReplyController } from './reply.controller';
+import { TypeOrmModule } from '@nestjs/typeorm';
+import { Reply } from './entities/reply.entity';
+import { ReplyAttachment } from './entities/reply-attachment.entity';
+import { ReplyRepository } from './repositories/reply.repository';
+import { ReplyAttachmentRepository } from './repositories/reply-attachment.repository';
+
+@Module({
+  imports: [TypeOrmModule.forFeature([Reply, ReplyAttachment])],
+  controllers: [ReplyController],
+  providers: [ReplyService, ReplyRepository, ReplyAttachmentRepository],
+})
+export class ReplyModule {}
diff --git a/src/reply/reply.service.ts b/src/reply/reply.service.ts
new file mode 100644
index 0000000..f60422d
--- /dev/null
+++ b/src/reply/reply.service.ts
@@ -0,0 +1,44 @@
+import { Injectable, NotFoundException } from '@nestjs/common';
+import { CreateReplyDto } from './dto/create-reply.dto';
+import { UpdateReplyDto } from './dto/update-reply.dto';
+import { ReplyRepository } from './repositories/reply.repository';
+// import { ReplyAttachmentRepository } from './repositories/reply-attachment.repository';
+import { Reply } from './entities/reply.entity';
+import { ReplyMessages } from 'src/common/enums/messages.enum';
+
+@Injectable()
+export class ReplyService {
+  constructor(
+    private readonly replyRepository: ReplyRepository,
+    // private readonly replyAttachmentRepository: ReplyAttachmentRepository,
+  ) {}
+
+  async create(createReplyDto: CreateReplyDto): Promise<Reply> {
+    const reply = this.replyRepository.create(createReplyDto);
+    await this.replyRepository.save(reply);
+    return reply;
+  }
+
+  async findAll(): Promise<Reply[]> {
+    return await this.replyRepository.find();
+  }
+
+  async findOneOrFail(id: string): Promise<Reply> {
+    const reply = await this.replyRepository.findOne({where: {id}});
+    if(!reply) throw new NotFoundException(ReplyMessages.REPLY_NOT_FOUND);
+
+    return reply;
+  }
+
+  async update(id: string, updateReplyDto: UpdateReplyDto): Promise<Reply> {
+    const reply = await this.findOneOrFail(id);
+    Object.assign(reply, updateReplyDto);
+    return reply;
+  }
+
+  async remove(id: string): Promise<Reply> {
+    const reply = await this.findOneOrFail(id);
+    await this.replyRepository.remove(reply);
+    return reply;
+  }
+}
diff --git a/src/reply/repositories/reply-attachment.repository.ts b/src/reply/repositories/reply-attachment.repository.ts
new file mode 100644
index 0000000..dccfee0
--- /dev/null
+++ b/src/reply/repositories/reply-attachment.repository.ts
@@ -0,0 +1,11 @@
+import { Injectable } from "@nestjs/common";
+import { Repository } from "typeorm";
+import { ReplyAttachment } from "../entities/reply-attachment.entity";
+import { InjectRepository } from "@nestjs/typeorm";
+
+@Injectable()
+export class ReplyAttachmentRepository extends Repository<ReplyAttachment> {
+    constructor(@InjectRepository(ReplyAttachment) replyAttachmentRepository: Repository<ReplyAttachment>) {
+        super(replyAttachmentRepository.target, replyAttachmentRepository.manager, replyAttachmentRepository.queryRunner);
+    }
+}
\ No newline at end of file
diff --git a/src/reply/repositories/reply.repository.ts b/src/reply/repositories/reply.repository.ts
new file mode 100644
index 0000000..e59f558
--- /dev/null
+++ b/src/reply/repositories/reply.repository.ts
@@ -0,0 +1,11 @@
+import { Repository } from "typeorm";
+import { Reply } from "../entities/reply.entity";
+import { InjectRepository } from "@nestjs/typeorm";
+import { Injectable } from "@nestjs/common";
+
+@Injectable()
+export class ReplyRepository extends Repository<Reply> {
+    constructor(@InjectRepository(Reply) replyRepository: Repository<Reply>) {
+        super(replyRepository.target, replyRepository.manager, replyRepository.queryRunner);
+    }
+}
\ No newline at end of file