When you create a Facebook group you can make it Open, Closed or Secret. In an open group anyone can join and everything is viewable by everyone online, including search engines. In a closed group, admins must approve members and only group members can see posted content. Secret groups are, of course, secret.
Subsequently, one may also ask, can you hide your groups on Facebook?
On your Timeline click the MORE tab below your Cover Photo, select Manage Sections, in the check box menu that opens you can select to not show a Groups section in the left column of your Timeline, in your About or in the MORE tab menu by unchecking the Groups item.
How do I make my groups on Facebook private?
Select "About" under your cover photo and scroll to the section you would like to hide. To configure your group visibility, for example, scroll to the Groups section. Click the pencil icon at the top right corner of that section and select "Edit Privacy," and then use the audience selector to limit visibility.
Do closed groups show up on Facebook?
Private (no one can see and it is invite-only), Closed (anyone can equest to join but content is private) and Open (everybody can see everything and join). Closed Groups do show up if you search for them in Facebook. But for some reason Closed Groups are not visible on users Timeline.