No, it will not create a Microsoft teams team automatically.

When you create a SharePoint online team site it will show you option to create a Microsoft teams and connect the SharePoint site to it like:

[![enter image description here][1]][1]


> Team sites that are not already connected to a group will first need to connect to a Microsoft 365 group before they can be added to Microsoft Teams.

**Reference**: [Create a Microsoft Team from SharePoint](https://support.microsoft.com/en-gb/office/create-a-microsoft-team-from-sharepoint-545973b6-c38f-426a-b2b6-16405a561628)


  [1]: https://i.sstatic.net/lcezC.png