I'm creating an office group using Microsoft Graph API. After that I would like to create a Microsoft Team which is associated with the group. I can do this step manually, but I'm wondering if it's also possible to do so via API.
Graph API doesn't seem to support Microsoft Teams yet. Am I correct?
You are correct, Teams is not yet part of the Graph API, nor do we yet have support for creating Teams. Both are on the road map, but I do not have an ETA for you at this time.
Actually you can do this semi-automatically using the beta API on Skype. Here is a GitHub project doing this from PowerShell: https://github.com/sanderdewit/teams-module
This approach is semi-automatically, because you need a user to sign-in once via a pop-up window. And for sure this is not a supported scenario.