diff --git a/backend/src/server/routes/v1/project-router.ts b/backend/src/server/routes/v1/project-router.ts
index 393b10c1a..02aa6999b 100644
--- a/backend/src/server/routes/v1/project-router.ts
+++ b/backend/src/server/routes/v1/project-router.ts
@@ -1,3 +1,4 @@
+import slugify from "@sindresorhus/slugify";
 import { z } from "zod";
 
 import {
@@ -79,7 +80,16 @@ export const registerProjectRouter = async (server: FastifyZodProvider) => {
           .enum(["true", "false"])
           .default("false")
           .transform((value) => value === "true"),
-        roles: z.string().trim().transform(decodeURIComponent).optional()
+        roles: z
+          .string()
+          .trim()
+          .transform(decodeURIComponent)
+          .refine((value) => {
+            if (!value) return true;
+            const slugs = value.split(",");
+            return slugs.every((slug) => slugify(slug.trim(), { lowercase: true }) === slug.trim());
+          })
+          .optional()
       }),
       params: z.object({
         workspaceId: z.string().trim()
@@ -118,7 +128,7 @@ export const registerProjectRouter = async (server: FastifyZodProvider) => {
     },
     onRequest: verifyAuth([AuthMode.JWT]),
     handler: async (req) => {
-      const roles = req.query.roles?.split(",") ?? [];
+      const roles = (req.query.roles?.split(",") || []).filter(Boolean);
       const users = await server.services.projectMembership.getProjectMemberships({
         actorId: req.permission.id,
         actor: req.permission.type,
diff --git a/backend/src/services/project-membership/project-membership-dal.ts b/backend/src/services/project-membership/project-membership-dal.ts
index 8a9d41cba..1692020fb 100644
--- a/backend/src/services/project-membership/project-membership-dal.ts
+++ b/backend/src/services/project-membership/project-membership-dal.ts
@@ -31,6 +31,26 @@ export const projectMembershipDALFactory = (db: TDbClient) => {
           if (filter.id) {
             void qb.where(`${TableName.ProjectMembership}.id`, filter.id);
           }
+          if (filter.roles && filter.roles.length > 0) {
+            void qb.whereExists((subQuery) => {
+              void subQuery
+                .select("role")
+                .from(TableName.ProjectUserMembershipRole)
+                .leftJoin(
+                  TableName.ProjectRoles,
+                  `${TableName.ProjectRoles}.id`,
+                  `${TableName.ProjectUserMembershipRole}.customRoleId`
+                )
+                .whereRaw(
+                  `"${TableName.ProjectUserMembershipRole}"."projectMembershipId" = "${TableName.ProjectMembership}"."id"`
+                )
+                .where((subQb) => {
+                  void subQb
+                    .whereIn(`${TableName.ProjectUserMembershipRole}.role`, filter.roles as string[])
+                    .orWhereIn(`${TableName.ProjectRoles}.slug`, filter.roles as string[]);
+                });
+            });
+          }
         })
         .join<TUserEncryptionKeys>(
           TableName.UserEncryptionKey,
@@ -126,11 +146,6 @@ export const projectMembershipDALFactory = (db: TDbClient) => {
           }
         ]
       });
-      if (filter.roles && filter.roles.length > 0) {
-        return members.filter((member) =>
-          member.roles.some((role) => filter.roles?.includes(role.role) || filter.roles?.includes(role.customRoleSlug))
-        );
-      }
       return members;
     } catch (error) {
       throw new DatabaseError({ error, name: "Find all project members" });
diff --git a/frontend/src/hooks/api/workspace/queries.tsx b/frontend/src/hooks/api/workspace/queries.tsx
index a3f45626e..2527f7bcf 100644
--- a/frontend/src/hooks/api/workspace/queries.tsx
+++ b/frontend/src/hooks/api/workspace/queries.tsx
@@ -445,7 +445,10 @@ export const useGetWorkspaceUsers = (
         {
           params: {
             includeGroupMembers,
-            roles: roles && roles.length > 0 ? encodeURIComponent(roles.join(",")) : undefined
+            roles:
+              roles && roles.length > 0
+                ? roles.map((role) => encodeURIComponent(role)).join(",")
+                : undefined
           }
         }
       );
diff --git a/frontend/src/pages/project/AccessControlPage/components/MembersTab/components/MembersTable.tsx b/frontend/src/pages/project/AccessControlPage/components/MembersTab/components/MembersTable.tsx
index 433d1941e..fd303f653 100644
--- a/frontend/src/pages/project/AccessControlPage/components/MembersTab/components/MembersTable.tsx
+++ b/frontend/src/pages/project/AccessControlPage/components/MembersTab/components/MembersTable.tsx
@@ -173,7 +173,7 @@ export const MembersTable = ({ handlePopUpOpen }: Props) => {
     setOrderDirection(OrderByDirection.ASC);
   };
 
-  const isTableFiltered = Boolean(Object.values(filter.roles).length);
+  const isTableFiltered = Boolean(filter.roles.length);
 
   const handleRoleToggle = useCallback(
     (roleSlug: string) =>