diff --git a/apps/server/src/entities/department.entity.ts b/apps/server/src/entities/department.entity.ts
new file mode 100644
index 0000000..d1b9fb9
--- /dev/null
+++ b/apps/server/src/entities/department.entity.ts
@@ -0,0 +1,49 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  UpdateDateColumn,
+  ManyToOne,
+  OneToMany,
+  JoinColumn,
+} from 'typeorm';
+
+export enum DepartmentType {
+  CAMPUS = 'campus',
+  DEPARTMENT = 'department',
+}
+
+@Entity('departments')
+export class Department {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ length: 100 })
+  name: string;
+
+  @Column({ name: 'parent_id', type: 'integer', nullable: true })
+  parentId: number;
+
+  @ManyToOne(() => Department, { nullable: true, onDelete: 'SET NULL' })
+  @JoinColumn({ name: 'parent_id' })
+  parent: Department;
+
+  @OneToMany(() => Department, (d) => d.parent)
+  children: Department[];
+
+  @Column({ length: 20, default: DepartmentType.DEPARTMENT })
+  type: string;
+
+  @Column({ name: 'sort_order', type: 'integer', default: 0 })
+  sortOrder: number;
+
+  @Column({ length: 20, default: 'active' })
+  status: string;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+
+  @UpdateDateColumn({ name: 'updated_at' })
+  updatedAt: Date;
+}
diff --git a/apps/server/src/entities/index.ts b/apps/server/src/entities/index.ts
index f8aecea..008d081 100644
--- a/apps/server/src/entities/index.ts
+++ b/apps/server/src/entities/index.ts
@@ -24,3 +24,5 @@ export { SyncLog } from './sync-log.entity';
 export { SyncState } from './sync-state.entity';
 export { ExpenseType } from './expense-type.entity';
 export { Notification, NotificationType } from './notification.entity';
+export { Department, DepartmentType } from './department.entity';
+export { UserDepartment } from './user-department.entity';
diff --git a/apps/server/src/entities/user-department.entity.ts b/apps/server/src/entities/user-department.entity.ts
new file mode 100644
index 0000000..b093b3f
--- /dev/null
+++ b/apps/server/src/entities/user-department.entity.ts
@@ -0,0 +1,38 @@
+import {
+  Entity,
+  PrimaryGeneratedColumn,
+  Column,
+  CreateDateColumn,
+  ManyToOne,
+  JoinColumn,
+  Unique,
+} from 'typeorm';
+import { User } from './user.entity';
+import { Department } from './department.entity';
+
+@Entity('user_departments')
+@Unique(['userId', 'departmentId'])
+export class UserDepartment {
+  @PrimaryGeneratedColumn()
+  id: number;
+
+  @Column({ name: 'user_id', type: 'integer' })
+  userId: number;
+
+  @ManyToOne(() => User, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'user_id' })
+  user: User;
+
+  @Column({ name: 'department_id', type: 'integer' })
+  departmentId: number;
+
+  @ManyToOne(() => Department, { onDelete: 'CASCADE' })
+  @JoinColumn({ name: 'department_id' })
+  department: Department;
+
+  @Column({ name: 'is_default', type: 'boolean', default: false })
+  isDefault: boolean;
+
+  @CreateDateColumn({ name: 'created_at' })
+  createdAt: Date;
+}