How to add 100+ users to a teams group all at once from a excel file email list

Hi @Jeffin Thomas,

Based on your information, you can bulk add member to a Teams group by using a csv file in Microsoft Entra ID:

• Sign to Microsoft Entra ID with Group administrator privilege at least (if you're an end user, you can contact your IT department and ask for help)
• Open Identity > Groups > All groups and select the Microsoft 365 group that backs your Team
• Choose Member > Bulk operations > Import member > Upload the csv file (which created based on the template suggested)
• Then select Submit to start bulk import members to the group

Microsoft does provide a detailed step by step guidance with illustration so you can refer to this article: Bulk upload to add or create members of a group - Microsoft Entra ID | Microsoft Learn

Hope this information will help. If you have any questions or need further assistance, please feel free to share them in the comments on this post so I can continue to support you.    

Thank you for your understanding and cooperation. I'm looking forward to your reply.

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Microsoft Teams does not support bulk-adding 100+ members directly from an Excel/CSV email list in the Teams client. Members must be added either:

1. Manually in Teams, or
2. By using Microsoft 365/Azure AD/PowerShell (not covered in the provided context).

From the available information, only the manual method in the Teams client is documented:

1. Open Microsoft Teams (desktop).
2. Go to the team where the users should be added.
3. Next to the team name, select More options (three dots) > Add member.
4. In the Add members box, start typing a name, distribution list, security group, or Microsoft 365 group, then select it from the results.
   • External people can be added as guests by typing their email addresses one by one.
5. When finished, select Add.
6. Optionally change any member to an owner by selecting the down arrow next to Member.

To add 100+ users “at once” without manually entering each email, the documented approach is to first put those users into a distribution list, security group, or Microsoft 365 group (outside of Teams), then add that group to the team using the steps above.

References:

• Add members to a team in Microsoft Teams