The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Administrative templates (5 members)
- Aerospace Engineers (5 members)
- Alex Jensen (8 members)
- Alice (4 members)
- Aliens (6 members)
- Amy (0 members)
- Amy's Family (20 members)
- Amy Farrah Fowler (271 members)
- Amy Mentioned (2 members)
- Animals (27 members)
- Announcer (1 member)
- Apartment 4A (152 members)
- Apartment 4B (75 members)
- Apartment Building Residents (22 members)
- Apartment Flag (9 members)
- Apology (3 members)
- Appearance Templates (81 members)
- Appeared As Themselves (32 members)
- Argument (2 members)
- Astronomers (1 member)
- Astrophysicists (11 members)
- Awards (2 members)
- Behind the scenes (2 members)
- Behind the scenes (The Big Bang Theory) (207 members)
- Behind the scenes (Young Sheldon) (25 members)
- Bernadette's parents (2 members)
- Bernadette Mentioned (4 members)
- Bernadette Rostenkowski-Wolowitz (267 members)
- Beverly Hofstadter (33 members)
- Big Bang Theory Wikians (2 members)
- Biologists (11 members)
- Blog posts (157 members)
- Books (10 members)
- Bride's Maid (2 members)
- Broadcaster (0 members)
- Broadcasters (7 members)
- Brothers (36 members)
- Bus (2 members)
- Business (1 member)
- California (3 members)
- Caltech Administrators (3 members)
- Caltech Faculty (23 members)
- Caltech Locations (5 members)
- Caltech Staff (9 members)
- Candidates for deletion (3 members)
- Captain Sweatpants (9 members)
- Cast (17 members)
- Cast Interviews (0 members)
- Cats (9 members)
- Characters (549 members)