diff --git a/.gitignore b/.gitignore
index de306388..18fe8f76 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,6 @@ vendor/
 # PHPUnit
 /.phpunit.cache
 .phpunit.result.cache
+
+# IDEs
+.idea/
\ No newline at end of file
diff --git a/lib/Resource/OrganizationMembership.php b/lib/Resource/OrganizationMembership.php
index 00667dcc..ce4ffe48 100644
--- a/lib/Resource/OrganizationMembership.php
+++ b/lib/Resource/OrganizationMembership.php
@@ -10,6 +10,7 @@
  * @property string $userId
  * @property string $organizationId
  * @property RoleResponse $role
+ * @property array<RoleResponse> $roles
  * @property 'active'|'inactive'|'pending' $status
  * @property string $createdAt
  * @property string $updatedAt
@@ -24,6 +25,7 @@ class OrganizationMembership extends BaseWorkOSResource
         "userId",
         "organizationId",
         "role",
+        "roles",
         "status",
         "createdAt",
         "updatedAt"
@@ -35,6 +37,7 @@ class OrganizationMembership extends BaseWorkOSResource
         "user_id" => "userId",
         "organization_id" => "organizationId",
         "role" => "role",
+        "roles" => "roles",
         "status" => "status",
         "created_at" => "createdAt",
         "updated_at" => "updatedAt"
diff --git a/lib/UserManagement.php b/lib/UserManagement.php
index 51d8a9ef..d6f04877 100644
--- a/lib/UserManagement.php
+++ b/lib/UserManagement.php
@@ -222,21 +222,29 @@ public function deleteUser($userId)
      * @param string $userId User ID
      * @param string $organizationId Organization ID
      * @param string|null $roleSlug Role Slug
+     * @param string|null $roleSlugs Role Slugs
      *
      * @throws Exception\WorkOSException
      *
      * @return Resource\OrganizationMembership
      */
-    public function createOrganizationMembership($userId, $organizationId, $roleSlug = null)
+    public function createOrganizationMembership($userId, $organizationId, $roleSlug = null, $roleSlugs = null)
     {
         $path = "user_management/organization_memberships";
 
         $params = [
             "organization_id" => $organizationId,
-            "user_id" => $userId,
-            "role_slug" => $roleSlug
+            "user_id" => $userId
         ];
 
+        if (!is_null($roleSlug)) {
+            $params["role_slug"] = $roleSlug;
+        }
+
+        if (!is_null($roleSlugs)) {
+            $params["role_slugs"] = $roleSlugs;
+        }
+
         $response = Client::request(
             Client::METHOD_POST,
             $path,
@@ -300,19 +308,26 @@ public function deleteOrganizationMembership($organizationMembershipId)
      * Update a User organization membership.
      *
      * @param string $organizationMembershipId Organization Membership ID
-     * @param string|null $role_slug The unique role identifier.
+     * @param string|null $role_slug The unique slug of the role to grant to this membership.
+     * @param string|null $role_slugs The unique slugs of the roles to grant to this membership.
      *
      * @throws Exception\WorkOSException
      *
      * @return Resource\OrganizationMembership
      */
-    public function updateOrganizationMembership($organizationMembershipId, $roleSlug = null)
+    public function updateOrganizationMembership($organizationMembershipId, $roleSlug = null, $roleSlugs = null)
     {
         $path = "user_management/organization_memberships/{$organizationMembershipId}";
 
-        $params = [
-            "role_slug" => $roleSlug
-        ];
+        $params = [];
+
+        if (!is_null($roleSlug)) {
+            $params["role_slug"] = $roleSlug;
+        }
+
+        if (!is_null($roleSlugs)) {
+            $params["role_slugs"] = $roleSlugs;
+        }
 
         $response = Client::request(
             Client::METHOD_PUT,
diff --git a/tests/WorkOS/UserManagementTest.php b/tests/WorkOS/UserManagementTest.php
index 9b9042c9..288f3603 100644
--- a/tests/WorkOS/UserManagementTest.php
+++ b/tests/WorkOS/UserManagementTest.php
@@ -893,7 +893,7 @@ public function testCreateOrganizationMembership()
         $params = [
             "organization_id" => $orgId,
             "user_id" => $userId,
-            "role_slug" => $roleSlug
+            "role_slug" => $roleSlug,
         ];
 
         $this->mockRequest(
@@ -912,6 +912,37 @@ public function testCreateOrganizationMembership()
         $this->assertSame($organizationMembership, $response->toArray());
     }
 
+    public function testCreateOrganizationMembershipWithRoleSlugs()
+    {
+        $userId = "user_01H7X1M4TZJN5N4HG4XXMA1234";
+        $orgId = "org_01EHQMYV6MBK39QC5PZXHY59C3";
+        $roleSlugs = ["admin"];
+        $path = "user_management/organization_memberships";
+
+        $result = $this->organizationMembershipResponseFixture();
+
+        $params = [
+            "organization_id" => $orgId,
+            "user_id" => $userId,
+            "role_slugs" => $roleSlugs,
+        ];
+
+        $this->mockRequest(
+            Client::METHOD_POST,
+            $path,
+            null,
+            $params,
+            true,
+            $result
+        );
+
+        $organizationMembership = $this->organizationMembershipFixture();
+
+        $response = $this->userManagement->createOrganizationMembership($userId, $orgId, null, $roleSlugs);
+
+        $this->assertSame($organizationMembership, $response->toArray());
+    }
+
     public function testGetOrganizationMembership()
     {
         $organizationMembershipId = "om_01E4ZCR3C56J083X43JQXF3JK5";
@@ -1080,6 +1111,28 @@ public function testUpdateOrganizationMembership()
         $this->assertSame($this->organizationMembershipFixture(), $response->toArray());
     }
 
+    public function testUpdateOrganizationMembershipWithRoleSlugs()
+    {
+        $organizationMembershipId = "om_01E4ZCR3C56J083X43JQXF3JK5";
+        $roleSlugs = ["admin"];
+        $path = "user_management/organization_memberships/{$organizationMembershipId}";
+
+        $result = $this->organizationMembershipResponseFixture();
+
+        $this->mockRequest(
+            Client::METHOD_PUT,
+            $path,
+            null,
+            ["role_slugs" => $roleSlugs],
+            true,
+            $result
+        );
+
+        $response = $this->userManagement->updateOrganizationMembership($organizationMembershipId, null, $roleSlugs);
+        $this->assertSame($this->organizationMembershipFixture(), $response->toArray());
+    }
+
+
     public function testDeactivateOrganizationMembership()
     {
         $organizationMembershipId = "om_01E4ZCR3C56J083X43JQXF3JK5";
@@ -1396,6 +1449,11 @@ private function organizationMembershipResponseFixture($status = "active")
             "role" => [
                 "slug" => "admin",
             ],
+            "roles" => [
+                [
+                    "slug" => "admin",
+                ],
+            ],
             "status" => $status,
             "created_at" => "2021-06-25T19:07:33.155Z",
             "updated_at" => "2021-06-25T19:07:33.155Z",
@@ -1415,6 +1473,11 @@ private function organizationMembershipListResponseFixture()
                         "role" => [
                             "slug" => "admin",
                         ],
+                        "roles" => [
+                            [
+                                "slug" => "admin",
+                            ]
+                        ],
                         "status" => "active",
                         "created_at" => "2021-06-25T19:07:33.155Z",
                         "updated_at" => "2021-06-25T19:07:33.155Z",
@@ -1438,6 +1501,11 @@ private function organizationMembershipFixture()
             "role" => [
                 "slug" => "admin",
             ],
+            "roles" => [
+                [
+                    "slug" => "admin",
+                ],
+            ],
             "status" => "active",
             "createdAt" => "2021-06-25T19:07:33.155Z",
             "updatedAt" => "2021-06-25T19:07:33.155Z",