What is Microsoft 365 Groups?
Also known as
Definition
A Microsoft 365 group gives a set of users shared access to a collection of connected resources:
- A shared Outlook inbox and calendar
- A SharePoint team site
- Planner
- OneNote notebook
- Clipchamp
- Power BI
- A team (if created from Microsoft Teams)
- Viva Engage (if created from Viva Engage)
- Roadmap (if you have Project for the web)
By default, anyone in your organization can create a group, unless you restrict that to specific users or disable self-service creation entirely.
Most users never see the group directly. They see the team in Teams or the SharePoint site. The group running underneath is invisible until something goes wrong—an owner leaves, a group gets deleted, or a migration surfaces dependencies nobody mapped.
tip
Before any migration or lifecycle cleanup, map what's connected to each group. Deleting a group removes every connected resource with it.
Why it matters
Groups is the membership layer behind Teams, SharePoint, and Exchange. What happens to a group affects every connected resource. That makes them central to migration planning, governance, and AI readiness.
- Migration: Groups connect Teams, SharePoint sites, mailboxes, and Planner to a single membership record. If a group is missed during planning, connected workloads arrive broken or orphaned at the destination.
- Governance & security: A group with no owner has no one accountable for who's in it. Orphaned groups are one of the most common sources of ungoverned access in Microsoft 365.
- AI readiness: If someone is still in a group they should have left, they can access—and Copilot can surface—content that was never meant for them.
What we see out there
Deleting a group takes more with it than expected.
Organizations that delete groups to reduce sprawl don't always realize the connected Team, SharePoint site, and shared mailbox go with it. A quick cleanup becomes a recovery project.
Group membership grants more access than anyone realized.
A single group connects Teams, SharePoint, Exchange, and Planner simultaneously. That scope often only becomes visible when someone actually looks during a migration, an access review, or a Copilot readiness conversation.
Frequently asked questions
How are Microsoft 365 Groups related to Teams?
Every team in Microsoft Teams has a Microsoft 365 group behind it. The group manages membership. When you add someone to a team in Teams, you're adding them to the underlying group, which also grants access to the connected SharePoint site, shared mailbox, and Planner. You can have a group without a team, but not a team without a group.
What happens when a group is deleted?
Everything connected to it is deleted: the team, the SharePoint site, the shared mailbox, the Planner boards. Microsoft holds deleted groups for 30 days, during which they can be restored. After that, recovery isn't possible. Archiving is almost always safer than deleting.
Who owns a Microsoft 365 group?
Group owners control membership and settings. Every group should have at least two—if the only owner leaves, nobody is accountable for access decisions. Ownership assigned at creation, and reviewed regularly, is what keeps groups governable at scale.
How do groups affect migration?
Groups need to exist in the target tenant before their connected workloads can migrate. If the group isn't there first, Teams content, SharePoint sites, and shared mailboxes won't arrive to the destination correctly. Group membership and ownership also need to be mapped between source and target. Migrating content without the right group structure means permissions break on arrival.
