diff --git a/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationChannel.java b/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationChannel.java
new file mode 100644
index 0000000..2804af5
--- /dev/null
+++ b/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationChannel.java
@@ -0,0 +1,7 @@
+package com.backendsystemdesignlab.notification.user.domain;
+
+public enum NotificationChannel {
+    PUSH,
+    SMS,
+    EMAIL
+}
diff --git a/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationPreference.java b/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationPreference.java
new file mode 100644
index 0000000..04b6d12
--- /dev/null
+++ b/src/main/java/com/backendsystemdesignlab/notification/user/domain/NotificationPreference.java
@@ -0,0 +1,55 @@
+package com.backendsystemdesignlab.notification.user.domain;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(
+        name = "notification_preferences",
+        uniqueConstraints = {
+                @UniqueConstraint(
+                        name = "uk_user_channel",
+                        columnNames = {"user_id", "channel"}
+                )
+        }
+)
+public class NotificationPreference {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "user_id")
+    private User user;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private NotificationChannel channel;
+
+    @Column(nullable = false)
+    private boolean enabled;
+
+    protected NotificationPreference() {}
+
+    public NotificationPreference(User user, NotificationChannel channel, boolean enabled) {
+        this.user = user;
+        this.channel = channel;
+        this.enabled = enabled;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public User getUser() {
+        return user;
+    }
+
+    public NotificationChannel getChannel() {
+        return channel;
+    }
+
+    public boolean isEnabled() {
+        return enabled;
+    }
+}
diff --git a/src/main/java/com/backendsystemdesignlab/notification/user/domain/Platform.java b/src/main/java/com/backendsystemdesignlab/notification/user/domain/Platform.java
new file mode 100644
index 0000000..a219475
--- /dev/null
+++ b/src/main/java/com/backendsystemdesignlab/notification/user/domain/Platform.java
@@ -0,0 +1,6 @@
+package com.backendsystemdesignlab.notification.user.domain;
+
+public enum Platform {
+    IOS,
+    ANDROID
+}
diff --git a/src/main/java/com/backendsystemdesignlab/notification/user/domain/User.java b/src/main/java/com/backendsystemdesignlab/notification/user/domain/User.java
new file mode 100644
index 0000000..34a0376
--- /dev/null
+++ b/src/main/java/com/backendsystemdesignlab/notification/user/domain/User.java
@@ -0,0 +1,36 @@
+package com.backendsystemdesignlab.notification.user.domain;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name = "users")
+public class User {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(length = 255)
+    private String email;
+
+    @Column(length = 30)
+    private String phoneNumber;
+
+    protected User() {}
+
+    public User(String email, String phoneNumber) {
+        this.email = email;
+        this.phoneNumber = phoneNumber;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+    public String getPhoneNumber() {
+        return phoneNumber;
+    }
+}
diff --git a/src/main/java/com/backendsystemdesignlab/notification/user/domain/UserDevice.java b/src/main/java/com/backendsystemdesignlab/notification/user/domain/UserDevice.java
new file mode 100644
index 0000000..6bfe963
--- /dev/null
+++ b/src/main/java/com/backendsystemdesignlab/notification/user/domain/UserDevice.java
@@ -0,0 +1,53 @@
+package com.backendsystemdesignlab.notification.user.domain;
+
+import jakarta.persistence.*;
+
+@Entity
+@Table(name = "user_devices")
+public class UserDevice {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @ManyToOne(fetch = FetchType.LAZY, optional = false)
+    @JoinColumn(name = "user_id")
+    private User user;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private Platform platform;
+
+    @Column(nullable = false, unique = true, length = 512)
+    private String deviceToken;
+
+    @Column(nullable = false)
+    private boolean active;
+
+    protected UserDevice() {}
+
+    public UserDevice(User user, Platform platform, String deviceToken) {
+        this.user = user;
+        this.platform = platform;
+        this.deviceToken = deviceToken;
+    }
+
+    public Long getId() {
+        return id;
+    }
+
+    public User getUser() {
+        return user;
+    }
+    public Platform getPlatform() {
+        return platform;
+    }
+
+    public String getDeviceToken() {
+        return deviceToken;
+    }
+
+    public boolean isActive() {
+        return active;
+    }
+}