diff --git a/lib/workos/user_management/organization_membership.ex b/lib/workos/user_management/organization_membership.ex
index 6d59b47..f0a614a 100644
--- a/lib/workos/user_management/organization_membership.ex
+++ b/lib/workos/user_management/organization_membership.ex
@@ -9,6 +9,7 @@ defmodule WorkOS.UserManagement.OrganizationMembership do
           id: String.t(),
           user_id: String.t(),
           organization_id: String.t(),
+          custom_attributes: map(),
           updated_at: String.t(),
           created_at: String.t()
         }
@@ -24,6 +25,7 @@ defmodule WorkOS.UserManagement.OrganizationMembership do
     :id,
     :user_id,
     :organization_id,
+    :custom_attributes,
     :updated_at,
     :created_at
   ]
@@ -34,6 +36,7 @@ defmodule WorkOS.UserManagement.OrganizationMembership do
       id: map["id"],
       user_id: map["user_id"],
       organization_id: map["organization_id"],
+      custom_attributes: map["custom_attributes"] || %{},
       updated_at: map["updated_at"],
       created_at: map["created_at"]
     }
diff --git a/test/support/user_management_client_mock.ex b/test/support/user_management_client_mock.ex
index ce328e2..3b8367c 100644
--- a/test/support/user_management_client_mock.ex
+++ b/test/support/user_management_client_mock.ex
@@ -34,6 +34,7 @@ defmodule WorkOS.UserManagement.ClientMock do
     "id" => "om_01H5JQDV7R7ATEYZDEG0W5PRYS",
     "user_id" => "user_01H5JQDV7R7ATEYZDEG0W5PRYS",
     "organization_id" => "organization_01H5JQDV7R7ATEYZDEG0W5PRYS",
+    "custom_attributes" => %{"department" => "Engineering"},
     "created_at" => "2023-07-18T02:07:19.911Z",
     "updated_at" => "2023-07-18T02:07:19.911Z"
   }
diff --git a/test/workos/user_management_test.exs b/test/workos/user_management_test.exs
index ae12076..fc0a61d 100644
--- a/test/workos/user_management_test.exs
+++ b/test/workos/user_management_test.exs
@@ -532,13 +532,18 @@ defmodule WorkOS.UserManagementTest do
 
       context |> ClientMock.get_organization_membership(assert_fields: opts)
 
-      assert {:ok, %WorkOS.UserManagement.OrganizationMembership{id: id}} =
+      assert {:ok,
+              %WorkOS.UserManagement.OrganizationMembership{
+                id: id,
+                custom_attributes: custom_attributes
+              }} =
                WorkOS.UserManagement.get_organization_membership(
                  opts
                  |> Keyword.get(:organization_membership_id)
                )
 
       refute is_nil(id)
+      assert custom_attributes == %{"department" => "Engineering"}
     end
   end