Guest Users in Microsoft 365

In today’s collaborative work environment, it’s essential to seamlessly interact with individuals outside your organization. Microsoft 365 offers a way to invite guest users—external individuals—into your tenant to work together within your environment. This capability fosters cooperation with clients, partners, or contractors, but it’s important to manage these external users carefully to ensure they only access what they need.

What Are Guest Users in Microsoft 365?

Guest users are individuals from outside your organization who are invited to collaborate and interact with your M365 environment. This could mean that you invite someone to become a guest in your tenant, or you may be a guest in someone else’s. While there are multiple ways to add guest users, it’s critical to control their access. Think of it like inviting someone into your home—you want them to be able to participate, but you don’t want them wandering into rooms they shouldn’t be in. The same applies here; guest users should only have access to resources that are relevant to them.

Adding Guest Users in Microsoft 365

There are several ways to add guest users in Microsoft 365. The most common method is through Entra or Azure Active Directory, where an admin can add or invite an external user. Additionally, if you’re managing a team, you can add guest users directly from the team settings. Another convenient option is when you share content, such as a file, from Microsoft Teams, OneDrive, or SharePoint. If guest access is enabled, sharing a file or folder with someone will automatically make them a guest user in your tenant. This entire process is controlled through settings that administrators can manage to ensure the right permissions are granted.

Guest User Capabilities and Limitations

Once added as a guest, these external users gain access to specific functionalities, but their capabilities are intentionally limited to maintain security. Guests don’t need a license and can become members of Microsoft 365 groups, allowing them to edit content, access Office web apps (such as Word and Excel), attend meetings, and more. However, their actions are governed by the permissions granted by your organization’s admins. They cannot be site owners, access certain APIs, or manage meetings or group membership. Additionally, while guests can join and participate in meetings, they cannot view detailed calendar events or manage meeting specifics in Teams. These limitations are designed to ensure that guests only access what they need, but settings can be further customized based on the organization’s needs.

Guests Can Become Members

For those situations where a guest user needs deeper integration into your tenant, it’s possible to elevate them to a full-fledged member. This is done through a multi-tenant organization setup. By going to the M365 Admin Center, you can configure multi-tenant collaboration settings under “org settings” and “org profile.” To make this work, you’ll need the tenant GUID ID from the other organization and at least one Entra ID P1 license on both ends (which can be trialed for 30 days if necessary). Once added as a member, the guest user will have the same access to M365 applications as any other internal user. This feature is particularly useful for situations where you need to collaborate closely with subsidiaries or parent companies sharing common resources.

The ability to add guest users in Microsoft 365 is a powerful tool for fostering collaboration, but it must be managed carefully to protect your organization’s data and privacy. By setting clear boundaries around what guests can and can’t access, you ensure that your Microsoft 365 environment remains secure while enabling smooth collaboration with external stakeholders. For deeper insights on handling guest users, make sure to check out the full Ask Sympraxis session recording for detailed discussions and audience questions that provide even more clarity on this topic.

All Resources

• Change the sharing settings for a site - SharePoint in Microsoft 365 | Microsoft Learn​
• Restrict SharePoint site access with Microsoft 365 groups and Entra security groups - SharePoint in Microsoft 365 | Microsoft Learn​
• Multitenant organization capabilities in Microsoft Entra ID

Do you have any questions for us? Continue the conversation on Twitter with the hashtag #AskSympraxis and mention @SympraxisC.