diff --git a/backend/cmd/server/main.go b/backend/cmd/server/main.go
index 8923aed9..3be0125b 100644
--- a/backend/cmd/server/main.go
+++ b/backend/cmd/server/main.go
@@ -609,10 +609,11 @@ func main() {
 	        KetoService:  ketoService,
 	})
 
-	admin.Get("/check", adminHandler.CheckAuth) // 기본 Admin 체크는 requireAdmin 없이 ApiKeyAuth로만 보호될 수 있음 (또는 추가 가능)	admin.Get("/stats", requireSuperAdmin, adminHandler.GetSystemStats)
+	admin.Get("/check", adminHandler.CheckAuth) // 기본 Admin 체크는 requireAdmin 없이 ApiKeyAuth로만 보호될 수 있음 (또는 추가 가능)
+	admin.Get("/stats", requireSuperAdmin, adminHandler.GetSystemStats)
 
 	// Tenant Management (Mixed roles, handler filters results)
-	admin.Get("/tenants", requireAdmin, tenantHandler.ListTenants)
+	admin.Get("/tenants", requireAnyUser, tenantHandler.ListTenants)
 	admin.Post("/tenants", requireSuperAdmin, tenantHandler.CreateTenant)
 	admin.Delete("/tenants/bulk", requireSuperAdmin, tenantHandler.DeleteTenantsBulk)
 	admin.Post("/tenants/:id/approve", requireSuperAdmin, tenantHandler.ApproveTenant)
diff --git a/backend/internal/handler/tenant_handler.go b/backend/internal/handler/tenant_handler.go
index 73bafe8e..03b4fb17 100644
--- a/backend/internal/handler/tenant_handler.go
+++ b/backend/internal/handler/tenant_handler.go
@@ -6,7 +6,6 @@ import (
 	"baron-sso-backend/internal/service"
 	"baron-sso-backend/internal/utils"
 	"errors"
-	"log/slog"
 	"strings"
 	"time"
 
@@ -114,16 +113,72 @@ func (h *TenantHandler) ListTenants(c *fiber.Ctx) error {
 	var err error
 
 	profile, _ := c.Locals("user_profile").(*domain.UserProfileResponse)
+	role := ""
+	if profile != nil {
+		role = domain.NormalizeRole(profile.Role)
+	}
 
-	// If Tenant Admin, only list manageable tenants
-	if profile != nil && domain.NormalizeRole(profile.Role) == domain.RoleTenantAdmin {
-		slog.Info("Listing manageable tenants for tenant admin", "userID", profile.ID)
-		tenants, err = h.Service.ListManageableTenants(c.Context(), profile.ID)
+	if role != domain.RoleSuperAdmin {
+		// Not a super admin: Only return the entire tree(s) of the tenants they belong to
+		allTenants, _, err := h.Service.ListTenants(c.Context(), 10000, 0, "")
 		if err != nil {
-			return errorJSON(c, fiber.StatusInternalServerError, "failed to list manageable tenants: "+err.Error())
+			return c.Status(fiber.StatusInternalServerError).JSON(fiber.Map{"error": err.Error()})
 		}
+
+		if profile != nil {
+			baseTenantIDs := []string{}
+			for _, t := range profile.ManageableTenants {
+				baseTenantIDs = append(baseTenantIDs, t.ID)
+			}
+			for _, t := range profile.JoinedTenants {
+				baseTenantIDs = append(baseTenantIDs, t.ID)
+			}
+			if profile.TenantID != nil {
+				baseTenantIDs = append(baseTenantIDs, *profile.TenantID)
+			}
+
+			// Try to find by companyCode if needed
+			if profile.CompanyCode != "" {
+				for _, t := range allTenants {
+					if strings.EqualFold(t.Slug, profile.CompanyCode) {
+						baseTenantIDs = append(baseTenantIDs, t.ID)
+					}
+				}
+			}
+
+			parentMap := make(map[string]string)
+			for _, t := range allTenants {
+				if t.ParentID != nil {
+					parentMap[t.ID] = *t.ParentID
+				}
+			}
+
+			findRoot := func(id string) string {
+				curr := id
+				for {
+					p, exists := parentMap[curr]
+					if !exists || p == "" {
+						break
+					}
+					curr = p
+				}
+				return curr
+			}
+
+			roots := make(map[string]bool)
+			for _, id := range baseTenantIDs {
+				roots[findRoot(id)] = true
+			}
+
+			// Filter tenants that belong to the same tree family
+			for _, t := range allTenants {
+				if roots[findRoot(t.ID)] {
+					tenants = append(tenants, t)
+				}
+			}
+		}
+
 		total = int64(len(tenants))
-		// Apply basic pagination if needed (optional for usually small number of manageable tenants)
 		if offset < len(tenants) {
 			end := offset + limit
 			if end > len(tenants) {
@@ -751,8 +806,8 @@ func (h *TenantHandler) DeleteTenantsBulk(c *fiber.Ctx) error {
 		return errorJSON(c, fiber.StatusBadRequest, "no IDs provided")
 	}
 
-	// Permission check: Super Admin can delete anything. 
-	// Tenant Admin should theoretically only delete manageable sub-tenants, 
+	// Permission check: Super Admin can delete anything.
+	// Tenant Admin should theoretically only delete manageable sub-tenants,
 	// but currently bulk delete is intended for Super Admin.
 	profile, _ := c.Locals("user_profile").(*domain.UserProfileResponse)
 	if profile == nil || domain.NormalizeRole(profile.Role) != domain.RoleSuperAdmin {