diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Client/Pages/Auth/Register.razor b/apps/web-client-tpos-net/src/WebClientTpos.Client/Pages/Auth/Register.razor
index 4f9d409a..f7ac6945 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Client/Pages/Auth/Register.razor
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Client/Pages/Auth/Register.razor
@@ -22,14 +22,25 @@
         <EditForm Model="@registerModel" OnValidSubmit="HandleRegister" FormName="RegisterForm">
             <DataAnnotationsValidator />
             
-            <div class="form-group">
-                <label for="reg-name">@L["Auth_Register_DisplayName"] *</label>
-                <InputText id="reg-name" 
-                          @bind-Value="registerModel.DisplayName" 
-                          class="form-input" 
-                          placeholder="John Doe" 
-                          autocomplete="name" />
-                <ValidationMessage For="() => registerModel.DisplayName" class="validation-message" />
+            <div class="form-row">
+                <div class="form-group">
+                    <label for="reg-lastname">@L["Auth_Register_LastName"] *</label>
+                    <InputText id="reg-lastname" 
+                              @bind-Value="registerModel.LastName" 
+                              class="form-input" 
+                              placeholder="Nguyễn" 
+                              autocomplete="family-name" />
+                    <ValidationMessage For="() => registerModel.LastName" class="validation-message" />
+                </div>
+                <div class="form-group">
+                    <label for="reg-firstname">@L["Auth_Register_FirstName"] *</label>
+                    <InputText id="reg-firstname" 
+                              @bind-Value="registerModel.FirstName" 
+                              class="form-input" 
+                              placeholder="Văn A" 
+                              autocomplete="given-name" />
+                    <ValidationMessage For="() => registerModel.FirstName" class="validation-message" />
+                </div>
             </div>
             
             <div class="form-group">
diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Client/Services/AuthService.cs b/apps/web-client-tpos-net/src/WebClientTpos.Client/Services/AuthService.cs
index 86a9a245..6080ef00 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Client/Services/AuthService.cs
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Client/Services/AuthService.cs
@@ -50,19 +50,22 @@ public class AuthService
     {
         try
         {
-            // EN: Build payload with FirstName/LastName from DisplayName (IAM requires these)
-            // VI: Tạo payload với FirstName/LastName từ DisplayName (IAM yêu cầu)
-            var parts = (dto.DisplayName ?? "User").Trim().Split(' ', 2);
+            // EN: Build payload with FirstName/LastName from form (IAM requires these)
+            // VI: Tạo payload với FirstName/LastName từ form (IAM yêu cầu)
             var payload = new
             {
                 dto.Email,
                 dto.Password,
-                FirstName = parts[0],
-                LastName = parts.Length > 1 ? parts[1] : parts[0],
-                DisplayName = dto.DisplayName
+                dto.FirstName,
+                dto.LastName
             };
 
-            var response = await _http.PostAsJsonAsync("/api/auth/register", payload);
+            // EN: Use PascalCase serialization to match backend RegisterUserCommand record params
+            // VI: Dùng PascalCase serialization để khớp với record params backend
+            var jsonOptions = new JsonSerializerOptions { PropertyNamingPolicy = null };
+            var jsonContent = JsonContent.Create(payload, options: jsonOptions);
+
+            var response = await _http.PostAsync("/api/auth/register", jsonContent);
             if (response.IsSuccessStatusCode)
             {
                 return (true, null);
diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/css/app.css b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/css/app.css
index 00325b52..2764a4fe 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/css/app.css
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/css/app.css
@@ -1020,6 +1020,22 @@ a {
 }
 
 /* Form Components */
+.form-row {
+    display: flex;
+    gap: var(--space-4);
+}
+
+.form-row>.form-group {
+    flex: 1;
+}
+
+@media (max-width: 480px) {
+    .form-row {
+        flex-direction: column;
+        gap: 0;
+    }
+}
+
 .form-group {
     margin-bottom: var(--space-6);
 }
diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/en-US.json b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/en-US.json
index cb83d390..0c0a8aeb 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/en-US.json
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/en-US.json
@@ -297,7 +297,8 @@
     "Auth_Login_Error": "Invalid email or password",
     "Auth_Login_RegisterLink": "Register now",
     "Auth_Login_Success": "Welcome {0}! Redirecting...",
-    "Auth_Register_DisplayName": "Display name",
+    "Auth_Register_FirstName": "First name",
+    "Auth_Register_LastName": "Last name",
     "Auth_Register_Error": "Registration failed",
     "Auth_Register_HaveAccount": "Already have an account?",
     "Auth_Register_LoginLink": "Sign In",
diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/vi-VN.json b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/vi-VN.json
index 0ebdff28..5652824b 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/vi-VN.json
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Client/wwwroot/locales/vi-VN.json
@@ -297,7 +297,8 @@
     "Auth_Login_Error": "Email hoặc mật khẩu không đúng",
     "Auth_Login_RegisterLink": "Đăng ký ngay",
     "Auth_Login_Success": "Chào mừng {0}! Đang chuyển hướng...",
-    "Auth_Register_DisplayName": "Tên hiển thị",
+    "Auth_Register_FirstName": "Tên",
+    "Auth_Register_LastName": "Họ",
     "Auth_Register_Error": "Đăng ký thất bại",
     "Auth_Register_HaveAccount": "Đã có tài khoản?",
     "Auth_Register_LoginLink": "Đăng nhập",
diff --git a/apps/web-client-tpos-net/src/WebClientTpos.Shared/DTOs/UserDto.cs b/apps/web-client-tpos-net/src/WebClientTpos.Shared/DTOs/UserDto.cs
index 20ddcfb5..3b97d96f 100644
--- a/apps/web-client-tpos-net/src/WebClientTpos.Shared/DTOs/UserDto.cs
+++ b/apps/web-client-tpos-net/src/WebClientTpos.Shared/DTOs/UserDto.cs
@@ -35,12 +35,20 @@ public class RegisterDto
     public string ConfirmPassword { get; set; } = string.Empty;
 
     /// <summary>
-    /// EN: User display name.
-    /// VI: Tên hiển thị của user.
+    /// EN: User first name.
+    /// VI: Tên của user.
     /// </summary>
-    [Required(ErrorMessage = "Tên là bắt buộc / Name is required")]
-    [StringLength(50, MinimumLength = 2, ErrorMessage = "Tên phải từ 2-50 ký tự / Name must be 2-50 chars")]
-    public string DisplayName { get; set; } = string.Empty;
+    [Required(ErrorMessage = "Tên là bắt buộc / First name is required")]
+    [StringLength(50, MinimumLength = 1, ErrorMessage = "Tên phải từ 1-50 ký tự / First name must be 1-50 chars")]
+    public string FirstName { get; set; } = string.Empty;
+
+    /// <summary>
+    /// EN: User last name.
+    /// VI: Họ của user.
+    /// </summary>
+    [Required(ErrorMessage = "Họ là bắt buộc / Last name is required")]
+    [StringLength(50, MinimumLength = 1, ErrorMessage = "Họ phải từ 1-50 ký tự / Last name must be 1-50 chars")]
+    public string LastName { get; set; } = string.Empty;
 
     /// <summary>
     /// EN: Accept terms of service.