diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index 0392a1d8..66677ee4 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -567,6 +567,7 @@ func main() {
 
 	// Signup Routes
 	signup := auth.Group("/signup")
+	signup.Get("/tenants", authHandler.GetActiveTenants)
 	signup.Post("/check-email", authHandler.CheckEmail)
 	signup.Post("/check-login-id", authHandler.CheckLoginID)
 	signup.Post("/send-email-code", authHandler.SendSignupEmailCode)
diff --git a/backend/internal/handler/auth_handler.go b/backend/internal/handler/auth_handler.go
index 27d1efa1..22fdab4a 100644
--- a/backend/internal/handler/auth_handler.go
+++ b/backend/internal/handler/auth_handler.go
@@ -463,6 +463,45 @@ func (h *AuthHandler) VerifySignupCode(c *fiber.Ctx) error {
 }
 
 // Signup - Finalize registration
+func (h *AuthHandler) GetActiveTenants(c *fiber.Ctx) error {
+	if h.TenantService == nil {
+		return errorJSON(c, fiber.StatusServiceUnavailable, "Tenant service unavailable")
+	}
+
+	// List all tenants (we use a large limit for now to get all affiliates)
+	tenants, _, err := h.TenantService.ListTenants(c.Context(), 1000, 0, "")
+	if err != nil {
+		return errorJSON(c, fiber.StatusInternalServerError, "Failed to fetch tenants")
+	}
+
+	type tenantResp struct {
+		ID      string   `json:"id"`
+		Name    string   `json:"name"`
+		Slug    string   `json:"slug"`
+		Type    string   `json:"type"`
+		Domains []string `json:"domains"`
+	}
+
+	var results []tenantResp
+	for _, t := range tenants {
+		if t.Status == domain.TenantStatusActive && (t.Type == domain.TenantTypeCompany || t.Type == domain.TenantTypeCompanyGroup) {
+			var domains []string
+			for _, d := range t.Domains {
+				domains = append(domains, d.Domain)
+			}
+			results = append(results, tenantResp{
+				ID:      t.ID,
+				Name:    t.Name,
+				Slug:    t.Slug,
+				Type:    t.Type,
+				Domains: domains,
+			})
+		}
+	}
+
+	return c.JSON(results)
+}
+
 func (h *AuthHandler) Signup(c *fiber.Ctx) error {
 	var req domain.SignupRequest
 	if err := c.BodyParser(&req); err != nil {
diff --git a/userfront/lib/core/services/auth_proxy_service.dart b/userfront/lib/core/services/auth_proxy_service.dart
index e651b4ae..5867402d 100644
--- a/userfront/lib/core/services/auth_proxy_service.dart
+++ b/userfront/lib/core/services/auth_proxy_service.dart
@@ -923,6 +923,17 @@ class AuthProxyService {
     }
   }
 
+  static Future<List<Map<String, dynamic>>> getActiveTenants() async {
+    final url = Uri.parse('$_baseUrl/api/v1/auth/signup/tenants');
+    final response = await http.get(url);
+
+    if (response.statusCode == 200) {
+      final List<dynamic> data = jsonDecode(response.body);
+      return data.cast<Map<String, dynamic>>();
+    }
+    return [];
+  }
+
   static Future<void> sendSignupCode(String target, String type) async {
     final path = type == 'email' ? 'send-email-code' : 'send-sms-code';
     final url = Uri.parse('$_baseUrl/api/v1/auth/signup/$path');
diff --git a/userfront/lib/features/auth/presentation/signup_screen.dart b/userfront/lib/features/auth/presentation/signup_screen.dart
index bde6317f..047799f1 100644
--- a/userfront/lib/features/auth/presentation/signup_screen.dart
+++ b/userfront/lib/features/auth/presentation/signup_screen.dart
@@ -54,6 +54,10 @@ class _SignupScreenState extends State<SignupScreen> {
   bool _isPasswordObscured = true;
   bool _isConfirmPasswordObscured = true;
 
+  // Dynamic Tenants
+  List<Map<String, dynamic>> _tenants = [];
+  final Map<String, String> _affiliateDomains = {};
+
   // Inline Errors
   String? _emailError;
   String? _phoneError;
@@ -66,20 +70,32 @@ class _SignupScreenState extends State<SignupScreen> {
   Timer? _phoneTimer;
   int _phoneSeconds = 0;
 
-  // 가족사 도메인 맵
-  final Map<String, String> _affiliateDomains = {
-    'hanmaceng.co.kr': 'HANMAC',
-    'samaneng.com': 'SAMAN',
-    'jangheon.co.kr': 'JANGHEON',
-    'hallasanup.com': 'HALLA',
-    'pre-cast.co.kr': 'PTC',
-    'baroncs.co.kr': 'BARON',
-  };
-
   @override
   void initState() {
     super.initState();
     _loadPolicy();
+    _fetchTenants();
+  }
+
+  Future<void> _fetchTenants() async {
+    try {
+      final tenants = await AuthProxyService.getActiveTenants();
+      if (mounted) {
+        setState(() {
+          _tenants = tenants;
+          _affiliateDomains.clear();
+          for (var t in tenants) {
+            if (t['domains'] != null) {
+              for (var d in (t['domains'] as List)) {
+                _affiliateDomains[d.toString().toLowerCase()] = t['slug'];
+              }
+            }
+          }
+        });
+      }
+    } catch (e) {
+      debugPrint('Failed to load tenants: $e');
+    }
   }
 
   Future<void> _loadPolicy() async {
@@ -1505,47 +1521,12 @@ class _SignupScreenState extends State<SignupScreen> {
                                           ),
                                           border: const OutlineInputBorder(),
                                         ),
-                                        items: [
-                                          DropdownMenuItem(
-                                            value: 'HANMAC',
-                                            child: Text(
-                                              tr('domain.company.hanmac'),
-                                            ),
-                                          ),
-                                          DropdownMenuItem(
-                                            value: 'SAMAN',
-                                            child: Text(
-                                              tr('domain.company.saman'),
-                                            ),
-                                          ),
-                                          DropdownMenuItem(
-                                            value: 'PTC',
-                                            child: Text(
-                                              tr(
-                                                'domain.company.ptc',
-                                                fallback: 'PTC',
-                                              ),
-                                            ),
-                                          ),
-                                          DropdownMenuItem(
-                                            value: 'JANGHEON',
-                                            child: Text(
-                                              tr('domain.company.jangheon'),
-                                            ),
-                                          ),
-                                          DropdownMenuItem(
-                                            value: 'BARON',
-                                            child: Text(
-                                              tr('domain.company.baron'),
-                                            ),
-                                          ),
-                                          DropdownMenuItem(
-                                            value: 'HALLA',
-                                            child: Text(
-                                              tr('domain.company.halla'),
-                                            ),
-                                          ),
-                                        ],
+                                        items: _tenants.map((t) {
+                                          return DropdownMenuItem<String>(
+                                            value: t['slug'],
+                                            child: Text(t['name'] ?? t['slug']),
+                                          );
+                                        }).toList(),
                                         onChanged: _isAffiliateEmail
                                             ? null
                                             : (val) => setState(