Distribution lists vs Microsoft 365 Groups
By Emil Björk · Microsoft ecosystem consultant, Gothenburg
How DLs, mail-enabled security groups, and Microsoft 365 Groups differ — and when to use each.
3 min read
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There are at least four kinds of "group" in Microsoft 365 that can receive email, and they behave differently. Picking the right one prevents a lot of awkward conversations a year later.
1. Distribution lists (DLs)
The classic Exchange distribution list. Mail sent to it fans out to every member's personal inbox. There's no shared storage, no SharePoint site, no Teams. Two flavours:
- Mail-enabled security groups also work as permission groups, granting access to resources.
- Plain distribution lists are mail-only.
DLs are simple, fast, and the right tool for announcements and broadcasts to a static set of recipients.
2. Microsoft 365 Groups
A Microsoft 365 Group is much more than an address: each group has a shared mailbox, a SharePoint team site, a OneNote notebook, a Planner plan, and (optionally) a Microsoft Teams team. Members can choose whether mail to the group arrives in their personal inbox (subscribe), in the group's mailbox only, or both.
Microsoft 365 Groups are the right tool for teams that collaborate — they bring an entire workspace, not just a list.
3. Shared mailboxes
A shared mailbox is a single inbox that multiple people read and send from. Mail doesn't fan out — it lands in one place, and delegated users see it as a folder in Outlook. Use for support@, sales@, info@ — addresses where you want a queue, not personal copies.
4. Dynamic distribution groups
A dynamic distribution group is a DL whose membership is computed at send time from a query — "all users in the Sales department," "all employees in London." Use for very large groups where maintaining membership manually is impractical.
When to pick what
| Scenario | Tool |
| --- | --- |
| Announcement to all of HR | Mail-enabled security group or Microsoft 365 Group |
| Project team that needs Teams + files | Microsoft 365 Group |
| support@ queue handled by 3 agents | Shared mailbox |
| Department-wide newsletter | Dynamic distribution group |
| External contact list (vendors, customers) | Mail contacts inside a DL |
Modernisation
Microsoft's direction is Microsoft 365 Groups for new team-style work and distribution groups upgraded to Microsoft 365 Groups for legacy DLs where it makes sense. Mail-enabled security groups remain because they still serve as permission grants. Outright distribution lists are not deprecated, but they're rarely the best new choice.
When in doubt: if the group's members collaborate together, pick a Microsoft 365 Group; if they're just on the same broadcast list, pick a DL or dynamic DL.
The cost of getting it wrong
Choosing a Microsoft 365 Group for what was really just a broadcast list is the more common mistake, and it's expensive precisely because of the extra infrastructure that comes with every Microsoft 365 Group: a SharePoint site, a Planner plan, a shared mailbox, and often a Teams team nobody uses — each one needing its own storage, lifecycle, and eventual cleanup once the initiative that created it ends. A tenant with hundreds of "groups" created purely for one-off announcements, each carrying an orphaned SharePoint site behind it, is a governance headache that a plain distribution list would never have created in the first place. The reverse mistake — a genuinely collaborative project team stuck on a bare distribution list — is less common but shows up as people falling back to email attachments and ad-hoc file shares because there's no shared workspace tied to the list at all.
Frequently asked questions
Can a distribution list be converted into a Microsoft 365 Group later without losing its address or members? Yes — Exchange Online supports upgrading an existing distribution list to a Microsoft 365 Group, preserving the email address and membership while adding the SharePoint site, Planner, and other collaboration resources; this is the standard remediation when a DL's usage has organically grown into genuine team collaboration.
Do dynamic distribution groups support Conditional Access targeting like security groups do? No — dynamic distribution groups are a mail-flow construct (computed at send time for email fan-out) rather than a security principal, so they can't be targeted by Conditional Access or app role assignment the way a dynamic security group can; a population that needs both email distribution and policy targeting needs a security group (potentially mail-enabled) rather than a dynamic distribution group.
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