How to add an email alias in Microsoft 365

Microsoft 365 admin guide · Using fictional example accounts · Updated October 2026

What does adding an alias actually do?

A secondary SMTP address delivers incoming mail to an existing mailbox. It does not create a new mailbox, new Microsoft 365 user or a second licence. The mailbox still has a primary address, which is normally the default address used for replies. Being able to send from an alias is a separate consideration and can depend on your organisation’s settings and mail client.

Before making the change

• Confirm which mailbox should receive the email and that the additional address is not already assigned elsewhere.
• Check that the domain is configured for your Microsoft 365 organisation.
• Use an account with the appropriate Exchange permissions and follow your organisation’s change process.

Option 1: Add an alias in the Exchange admin centre

1. Open the Exchange admin centre and go to Recipients → Mailboxes.
2. Select the mailbox you need to change.
3. Under General → Email addresses, open the option to manage address types.
4. Add an SMTP email address, select the domain, enter the new alias and save.
5. Reopen the mailbox details to confirm the additional address appears.

Option 2: Add an alias with Exchange Online PowerShell

After connecting securely to Exchange Online with the relevant permissions, a typical example is:

Set-Mailbox -Identity "[email protected]" -EmailAddresses @{Add="[email protected]"}

The @{Add=...} form adds an address without replacing all existing ones. Replacing the full EmailAddresses property by mistake could remove required addresses.

Get-Mailbox -Identity "[email protected]" | Select-Object -ExpandProperty EmailAddresses

Check the returned addresses and test receipt of mail sent to the new alias. The examples use fictional accounts; adapt them carefully to your own environment.

Can I use TenantPilot instead?

Yes. TenantPilot includes an Add alias task for suitable Exchange Online mailboxes. You can find the task, choose the mailbox, review the proposed change and run it with an authorised account—without memorising the PowerShell syntax.

Common questions

Will the mailbox receive email at both addresses?

Yes, provided the addresses are valid, accepted by your organisation and mail delivery is configured correctly.

Does an alias give someone else access to the mailbox?

No. Access permissions and aliases are different things. If a colleague needs access to an existing mailbox, see our shared-mailbox permissions guide.

Does this apply to hybrid organisations?

Some directory-synchronised environments require the address change in the on-premises source directory instead. Check where the recipient is managed before making changes.