Connect to new Microsoft 365 group: CSOM development

The SharePoint client-side object model (CSOM) provides access to the SharePoint object model from code that is running locally or on a different server than SharePoint.


It is not supported to connect a Communication site to Microsoft 365 group.


Before you get started, make sure that you're familiar with the following:

You also need to reference the Microsoft.SharePointOnline.CSOM NuGet package (version 16.1.6906.1200 or later).

CSOM code example

The following example shows how to create a Microsoft.Online.SharePoint.TenantAdministration.Tenant object and call the CreateGroupForSite method to return a list of themes.


  • The URL used to create the context object includes the -admin suffix, because TenantAdministration methods work with the admin site.
  • Create a Tenant instance with the Tenant constructor, and then call the methods on that instance.
using System.Security;
using Microsoft.SharePoint.Client;
using Microsoft.Online.SharePoint.TenantAdministration;
using Microsoft.Online.SharePoint.TenantManagement;


ClientContext ctx = new ClientContext("");
var pwd = "mypassword";
var passWord = new SecureString();
foreach (char c in pwd.ToCharArray()) passWord.AppendChar(c);
ctx.Credentials = new SharePointOnlineCredentials("", passWord);
Tenant tenant = new Tenant(ctx);
tenant.CreateGroupForSite("", "display-name-for-group", "alias-for-group", true);

Methods in Microsoft.Online.SharePoint.TenantAdministration.Tenant class

Use the following methods to create a new Microsoft 365 Group and attach it to an existing site.

CreateGroupForSite method

Create a new Microsoft 365 group and attach it to an existing site. After this succeeds for a given site, calling it again with the same site will throw an Exception.

Namespace: Microsoft.Online.SharePoint.TenantAdministration.Tenant
Return type: void

Parameter Type Description
siteUrl string URL of the site to connect to a new Microsoft 365 group.
displayName string Display Name group to create.
alias string Alias of the new group to create.
isPublic bool Whether the group is public or private.
optionalParams GroupCreationParams An optional set of creation parameters for the group.

type: Microsoft.Online.SharePoint.TenantAdministration.GroupCreationParams

Property Type Description
Description string Gets and sets the group description.
Owners string[] Gets and sets the group owners. These should be the principal names of the users.
CreationOptions string[] Gets and sets the group's creation options.
Classification string Gets and sets the group's data classification.

See also