How to Set Up a Shared Calendar for All Users in Microsoft 365

Keeping everyone on the same page is easier with a shared calendar. In many organizations, management uses it to post key events, while employees add their own updates. In this article, you will learn how to set up a shared calendar in Microsoft 365 that every user can access.

Step 1. Create a shared mailbox

To create a shared mailbox in Microsoft 365, follow the steps below:

1. Sign in to Microsoft 365 admin center.
2. Expand Teams & groups > Shared mailboxes.
3. Click Add a shared mailbox.
4. Fill in the shared mailbox name and email.

You can use a user mailbox instead of a shared mailbox. Remember that a user mailbox needs a license, and a shared mailbox doesn’t.

Step 2. Create a mail-enabled security group

Create a mail-enabled security group and add the users to it by following the steps below:

1. Sign in to Microsoft 365 admin center.
2. Expand Teams & groups > Active teams & groups.
3. Click Security groups.
4. Click Add a mail-enabled security group.

5. Give the mail-enabled security group a name (SG-ChicagoCal-Mail) and a description.
6. Click Next.

7. Click Assign owners.
8. Add the owners.
9. Click Next.

10. Click Add members.
11. Add the members.
12. Click Next.

13. Enter a group email address.
14. Click Next.

15. Click Create group.

Step 3. Add permission to shared calendar

Add the mail-enabled security group as editor permissions to the shared mailbox calendar by following these steps:

1. Install Exchange Online PowerShell.
2. Connect to Exchange Online PowerShell.

Connect-ExchangeOnline

3. Check the calendar name. This is because the calendar name may vary from country to country. For example, it’s called Agenda in the Netherlands.

Get-Mailbox -Identity "ChicagoCal@exoip.com" | Get-MailboxFolderStatistics -FolderScope Calendar | Format-Table Identity,Name

The output appears.

Identity                          Name
--------                          ----
ChicagoCal20250827065653\Calendar Calendar

4. Add the mail-enabled security group (which contains the users) as editor permissions to the calendar.

Add-MailboxFolderPermission -Identity "ChicagoCal@exoip.com:\Calendar" -User "SG-Chicago-Mail" -AccessRights Editor

The output appears.

FolderName User               AccessRights  SharingPermissionFlags
---------- ----               ------------  ----------------------
Calendar   SG-ChicagoCal-Mail {Editor}

You can read more about Manage calendar permissions in Office 365 with PowerShell.

Step 4. Test shared calender

Once everything is set, add the shared calendar to Outlook and verify that users can add new entries and view each other’s entries.

That’s it!

Read more: Block sign-in from shared mailboxes »

Conclusion

You learned how to set up a shared calendar for all users in the organization. First, create a user or shared mailbox. Next, create a mail-enabled security group and add the users to it. Lastly, add the mailbox calendar permission by linking the mail-enabled security group to the shared mailbox calendar.

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