When you remove a collaborator from your project, they lose read/write access to your repository. If the repository is private and the person has created a fork, then that fork is also deleted.

Deleting forks of private repositories

While forks of private repositories are deleted when a collaborator is removed, the person will still retain any local clones of your repository.

Removing collaborator permissions from a person contributing to a repository

  1. On GitHub, navigate to the main page of the repository.

  2. Under your repository name, click Settings. Repository settings button

  3. In the left sidebar, click Collaborators & teams. Collaborators tab

  4. Next to the collaborator you want to remove, click the X icon. Remove link

Further reading