diff --git a/CHANGELOG.md b/CHANGELOG.md
index 43f2101..8e37c87 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,9 @@ All notable changes to this project will be documented in this file.
 
 ## Unreleased
 
+### Fixed
+- namespace limitation [mabhi](https://github.com/mabhi)
+
 ## [0.2.0] - 2023-01-27
 
 ## Fixed
diff --git a/pkg/service/group.go b/pkg/service/group.go
index 087dcfe..a92a119 100644
--- a/pkg/service/group.go
+++ b/pkg/service/group.go
@@ -4,6 +4,7 @@ import (
 	"context"
 	"database/sql"
 	"fmt"
+	"regexp"
 	"strings"
 	"time"
 
@@ -102,6 +103,8 @@ func (s *groupService) createGroupRoleRelations(ctx context.Context, db bun.IDB,
 	var grs []models.GroupRole
 	var ps []*authzv1.Policy
 	var rids []uuid.UUID
+	regexc := regexp.MustCompile(`^[a-z0-9]([-a-z0-9]*[a-z0-9])?$`)
+
 	for _, pnr := range projectNamespaceRoles {
 		role := pnr.GetRole()
 		entity, err := dao.GetByName(ctx, db, role, &models.Role{})
@@ -204,6 +207,14 @@ func (s *groupService) createGroupRoleRelations(ctx context.Context, db bun.IDB,
 			}
 
 			namespace := pnr.GetNamespace()
+			match := regexc.MatchString(namespace)
+			if !match {
+				return &userv3.Group{}, nil, fmt.Errorf("namespace %q is invalid", namespace)
+			}
+			if len(namespace) < 1 || len(namespace) > 63 {
+				return &userv3.Group{}, nil, fmt.Errorf("namespace %q is invalid. must be no more than 63 characters", namespace)
+			}
+
 			pgnrObj := models.ProjectGroupNamespaceRole{
 				CreatedAt:      time.Now(),
 				ModifiedAt:     time.Now(),