Shared Mailbox vs Distribution List in Microsoft 365: Which to Use

If you manage email for a UK business using Microsoft 365, you've almost certainly been asked: "Should we use a shared mailbox or a distribution list for this?" It's a common question because both features let multiple people receive messages sent to a single address — but they work in fundamentally different ways.

Choosing the wrong one leads to missed emails, duplicated replies, and confused customers. This guide explains exactly what each option does, when to use it, and how to set them up.

What Is a Shared Mailbox?

A shared mailbox is a full mailbox that multiple users can open, read, and reply from. It appears as a separate mailbox in Outlook alongside each user's personal inbox.

Key Characteristics

• Shared inbox — every member sees all incoming messages and can read them
• Send-as or send-on-behalf — members reply from the shared address (e.g., sales@yourcompany.co.uk) so the recipient doesn't see individual names
• No extra licence — shared mailboxes are free in Microsoft 365 up to 50 GB
• Conversation tracking — everyone can see previous replies, reducing duplicate responses
• Calendar included — useful for team scheduling (e.g., a support rota calendar)
• Stored centrally — messages stay in the shared mailbox, not in individual inboxes

Common Use Cases

• info@, sales@, support@, accounts@ — any address where multiple staff handle enquiries
• Project-specific mailboxes where the whole team needs visibility
• Compliance or record-keeping scenarios where a permanent, searchable email archive is needed

What Is a Distribution List (Distribution Group)?

A distribution list is simply an email address that forwards incoming messages to a predefined group of recipients. There's no shared mailbox behind it — each member receives a copy in their own inbox.

Key Characteristics

• One-to-many delivery — a message sent to the list is copied to every member's personal inbox
• No shared view — members can't see whether someone else has already replied
• Replies come from the individual — when a member replies, it goes from their personal address (unless they manually change the From field)
• No licence required — distribution lists are free
• No calendar or shared storage

Common Use Cases

• Company-wide announcements (e.g., allusers@yourcompany.co.uk)
• Department newsletters or broadcast communications
• Sending to a group where replies aren't expected or where individual follow-up is fine

Head-to-Head Comparison

Feature	Shared Mailbox	Distribution List
Shared inbox view	Yes	No
Send-as capability	Yes	No
Conversation tracking	Yes	No
Calendar	Yes	No
Licence cost	Free (up to 50 GB)	Free
Best for	Collaborative replies	Broadcast messages

What About Microsoft 365 Groups?

There's a third option worth knowing about: Microsoft 365 Groups. A Group gives you a shared mailbox, calendar, SharePoint library, Planner board, and a connected Teams channel — all in one package.

Groups are ideal when collaboration goes beyond email. If a team needs to share files, manage tasks, and communicate via chat as well as email, a Microsoft 365 Group covers all of it. Learn more about the wider Microsoft 365 ecosystem.

How to Create a Shared Mailbox

1. Sign in to the Microsoft 365 admin centre at admin.microsoft.com.
2. Go to Teams & groups → Shared mailboxes.
3. Click Add a shared mailbox.
4. Enter a display name (e.g., "Sales Enquiries") and email address (e.g., sales@yourcompany.co.uk).
5. Click Save, then add the users who need access.
6. Under Members, assign Send As or Send on Behalf permissions as needed.

Members will see the shared mailbox appear in Outlook within an hour.

How to Create a Distribution List

1. In the admin centre, go to Teams & groups → Distribution lists.
2. Click Add a group and select Distribution.
3. Name the list and assign an email address.
4. Add members.
5. Choose whether external senders can email the list (useful for customer-facing addresses).

Quick Decision Guide

Use this simple framework to decide:

• Need to collaborate on replies? → Shared Mailbox
• Need to broadcast information? → Distribution List
• Need email + files + tasks + chat? → Microsoft 365 Group
• Need a customer-facing address with tracked replies? → Shared Mailbox
• Need an internal announcement channel? → Distribution List

Need Help Configuring Your Email Setup?

Getting email right is foundational to your business communications. If you're unsure about the best setup, or you need to restructure an existing Microsoft 365 environment, a managed IT provider can audit your current configuration and recommend the optimal approach.

Get a free IT quote to connect with vetted UK providers who specialise in Microsoft 365.