What Is a Microsoft 365 Group?
A Microsoft 365 Group (formerly Office 365 Group) is an identity and access management object in Entra ID that provides a shared membership across multiple Microsoft 365 services. It is the single source of truth for permissions across workloads like Teams, SharePoint, Exchange, and Planner.
When a Group is created, it acts as the backbone of collaboration. You are not provisioning individual tools — you are provisioning a shared identity that governs access, ownership, and data across the ecosystem.
What Gets Created with a Group?
The exact resources provisioned depend on where the Group is created, but in modern Microsoft 365, a Group can include:
- SharePoint Site — Document library and collaboration portal. Every Group gets this.
- Exchange Shared Mailbox & Calendar — Shared inbox and calendar visible to all members. Can be configured to deliver copies to members' personal inboxes.
- Microsoft Teams Team — Created automatically only when the Group originates from Teams; can be added later otherwise.
- Planner Plan — Created automatically from the Planner experience; optional when created elsewhere.
- OneNote Notebook — Shared notebook provisioned with every Group.
- Stream (on SharePoint) — Group video storage, now integrated directly into SharePoint document libraries.
- Power BI Workspace — Available if Power BI licensing is in place.
- Project / Roadmap — Available with Project for the Web licensing.
- Loop Workspaces — Increasingly tied to Group-backed collaboration in modern tenants.
Important: Membership is unified. When a user is added to the Group, they receive access to all associated resources. You cannot restrict access by individual application at the Group level. Private channels in Teams remain the exception — members must be explicitly invited to those.
What About Viva Engage (Formerly Yammer)?
Yammer has been rebranded to Viva Engage and its relationship with Microsoft 365 Groups has evolved. Modern Viva Engage communities can be connected to Microsoft 365 Groups and leverage Entra ID identity and SharePoint storage. However, legacy Yammer-native groups may not have full M365 resource integration.
Viva Engage communities still focus on enterprise social engagement rather than structured team collaboration. They do not support a Teams team or full Exchange mailbox/calendar integration in the same way other Group-backed workloads do.
How Groups Are Created
Users typically do not create Groups directly. They create them indirectly through applications — and the entry point determines which resources are auto-provisioned.
| Created From | Primary Experience | Auto-Provisioned Resources |
|---|---|---|
| Microsoft Teams | Chat-based collaboration | Team + SharePoint + Mailbox + Calendar + OneNote |
| SharePoint | Document collaboration | Site + Mailbox + Calendar + OneNote (no Team unless added) |
| Outlook | Email-based collaboration | Mailbox + Calendar + SharePoint + OneNote |
| Planner | Task management | Plan + SharePoint + Mailbox + Calendar + OneNote |
| Viva Engage | Enterprise social | Community + SharePoint (limited Exchange integration) |
The entry point defines the user experience, but the Group is always the backbone.
Group Roles
- Owners — Manage membership, settings, naming, description, and Group picture. Can delete conversations in the shared inbox and control guest access.
- Members — Full access to all resources tied to the Group. Can invite others if the Owner has not revoked that permission.
- Guests — External users from another organization invited to collaborate within the Group's shared resources.
Every Group should have at least two Owners to prevent orphaned resources if a single Owner leaves the organization.
Group Limits
- Maximum of 100 Owners per Group
- A standard (non-admin) user can create up to 250 Groups
- Shared Mailbox maximum size: 50 GB
- A user can be a member of up to 7,000 Groups
Common Misconceptions
Misconception: Teams is separate from Groups.
Reality: Every Team is backed by a Microsoft 365 Group. Deleting the Group deletes the Team and all associated resources.
Misconception: You can control access per application within a Group.
Reality: Membership is unified across all connected workloads. Fine-grained control requires additional configuration like private channels or site permission adjustments.
Misconception: Groups are optional.
Reality: Groups are required for modern collaboration workloads in Microsoft 365. If you are using Teams, SharePoint team sites, or Planner, you are using Groups.
Governance Considerations
Without governance, tenants quickly accumulate abandoned and duplicate Groups. Key governance practices include:
- Control who can create Groups using Entra ID security group restrictions
- Implement naming conventions and sensitivity labels
- Use Group expiration policies to clean up inactive Groups automatically
- Monitor sprawl across Teams and SharePoint with admin reporting
- Align Groups with compliance requirements such as DLP, retention policies, and eDiscovery
Final Takeaway
Microsoft 365 Groups are not just a feature — they are the foundation of collaboration across the entire Microsoft ecosystem. Whether users are creating a Team, a SharePoint site, or a Planner plan, they are fundamentally creating a shared identity that governs access, ownership, and data.
If you understand Microsoft 365 Groups, you understand how Microsoft 365 actually works.