Microsoft Teams provides a unified collaboration experience to all users, including Guests (members outside of your organization and Microsoft 365 tenants) who have been invited to Teams.
The first step to ensure Guests can be added to Microsoft Teams is configuring Guest access in Azure AD and Microsoft Admin Centers. Read our Ultimate Guide: How to enable, disable and configure external sharing and Guest access in Microsoft 365 to learn more.
Once Guest access has been configured and enabled, adding Guests to Microsoft Teams is very easy – Team owners simply need to enter an email address in the Team management tab and the Guest will be added. They won’t have access to the Team for a couple of hours but will be visible under the Members & Guests section under Team Members.
When a guest is invited to join a team, they will receive a welcome email message. This message includes some information about the team and what to expect now that they’re a member. To access the Team that the Guest was invited to, the Guest must accept the invitation by selecting Open Microsoft Teams in the email message.

The default Guest settings in Microsoft Teams permit the Guests to collaborate with members, Team owners, and other Guests in many ways:
Guests do not have the default permissions to:
What’s interesting is that the default Guest permissions in Microsoft Teams cannot supersede the permissions set for the members of your Team. For example, if your default member permissions restrict channel creation or updating, or message deletion, your Guests also won’t be able to perform these actions.
Here is an example of the permissions for members of a Team.

Below you will see that the selections you made for the Team member permissions directly impact the default Guest permissions:

Microsoft Teams Admin Centre allows you some control over what Guests can and cannot do in Microsoft Teams.
To change the default settings, you will need to access the Microsoft Teams Admin Centre, find the users management menu, and click on Guest Access.
In there you will be able to toggle on and off various settings for each capability under Calling, Meetings, and Messaging.

Enabling Guest access in Microsoft Teams opens up many new collaboration opportunities, but also exposes your tenant and information within it to some threats. Subscribe to our newsletter below to receive the latest blogs about the considerations, risks, and risk mitigation techniques related to external sharing and enabling Guest access in your tenant.
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