Using Classic Outlook on Windows for personal email, calendar, and contact management
Hi Diane,
The maximum at the moment is 250 of people in one Teams meeting. This goes regardless of application (web or desktop) or whether the attendees are guests or users.
For more information, please refer to the article - https://docs.microsoft.com/en-us/microsoftteams/limits-specifications-teams.
Feel free to let me know if you have more questions.
Best regards,
Nemanja