SharePoint Stack Exchange is a question and answer site for SharePoint enthusiasts. It only takes a minute to sign up.
Sign up to join this community
In SharePoint Online, you can add a user as owner to a group even if they have no access to a site.
However, I can't seem to find a way to allow them to really "own" the group (view and add members, etc.) without giving them permissions on the site (such as Full Control).
Is there a way to allow a user to add users to a group without allowing him/her any ability to modify permissions elsewhere on the site?
You probably need to grant them read access on the top level of the site to have access to the site aspx pages. You could even restrict that access to only the site assets and site pages library if needed. Making them a group owner in no way gives them rights anywhere else.
