Manage guest access in Microsoft 365 groups
By default, guest access for Microsoft 365 groups is turned on for your organization. Admins can control whether to allow guest access to groups for their whole organization or for individual groups.
When it's turned on, group members can invite guest users to a Microsoft 365 group through Outlook on Web. Invitations are sent to the group owner for approval.
Once approved, the guest user is added to the directory and the group.
Yammer Enterprise networks that are in Native Mode or the EU Geo do not support network guests. Microsoft 365 Connected Yammer groups do not currently support guest access, but you can create non-connected, external groups in your Yammer network. See Create and manage external groups in Yammer for instructions.
Guest access in groups is often used as part of a broader scenario that includes SharePoint or Teams. These services have their own guest sharing settings. For complete instructions for setting up guest sharing across groups, SharePoint, and Teams, see:
Manage groups guest access
If you want to enable or disable guest access in groups, you can do so in the Groups.
In the admin center, go to Show all > Settings > Org settings and on the Services tab, select Microsoft 365 Groups.
On the Microsoft 365 Groups page, choose whether you want to let people outside your organization access group resources or let group owners add people outside your organization to groups.
Add guests to a Microsoft 365 group from the admin center
In the admin center, go to the Groups > Groups.
Click the group you want to add the guest to, and select View all and manage members on the Members tab.
Select Add members, and choose the name of the guest you want to add.
If you want to add a guest to the directory directly, you can Add Azure Active Directory B2B collaboration users in the Azure portal.
If you want to edit any of a guest's information, you can Add or update a user's profile information using Azure Active Directory.
Block guest users from a specific group (article)
Manage group membership in the Microsoft 365 admin center (article)
Azure Active Directory access reviews (article)