Stuart's Cousin is an unseen character who was mentioned by Stuart in "The Excelsior Acquisition". Stuart brings up the fact that he frequently attends weddings with this cousin. Stuart also mentions that this cousin was getting married in the same episode, and he asks Penny to be his date (though she can bring Leonard) as an exchange for Stan Lee's address so that Sheldon can meet him.
- When Stuart brings up his cousin, he never really confirms whether or not the cousin is a woman, so there's a possibility that Stuart's cousin is male.
- It's unclear if this cousin of Stuart's is the child of Stuart's Uncle, who is Stan Lee's dermatologist.