| Kirk Simpson|
|Relatives|| Father: Bart Simpson|
|First Appearance||"Holidays of Future Passed"|
|Voiced By||Pamela Hayden|
- “It smells like dog, but there's no dog!”
- ―Bart's Younger Son
He first arrives with his brother at The Lofts at Springfield Elementary as their mother forces them to associate more with their father Bart. Bart lies to them by assuring them it will be the best Christmas ever, but they can read minds and are aware of it. Later Bart becomes jealous after learning Jenda has remarried. Furthermore, their grandfather Homer spent time with them, which again made Bart jealous. By the end of the episode, he and his brother made amends with their father and indeed had the best Christmas ever, as Bart had promised them. He or his brother might have appeared briefly in a photo owned by an elderly Bart.
- Neither of the children's names are revealed.
- Their ages are also unknown, but considering the fact that Bart had been living with Homer and Marge until 6 years before the events from "Holidays of Future Passed" they are most likely no older than 5.
- Judging by his usage of glasses, he might be a nerd. That and the fact that he is younger than his brother seems to make him a slight mirror to his aunt Lisa.
- He bears some resemblance to Bart when he was forced to wear horn-rimmed glasses as a result of sight problems regarding reading from the blackboard in "The Last Temptation of Homer".
- He and his brother can both read people's minds, so it is implied that they are telepathic.
- Episode – "Holidays of Future Passed"
- Episode – "A Totally Fun Thing That Bart Will Never Do Again" (Possible photo appearance)
- Episode – "Days of Future Future"