"HOMR" is the ninth episode of the twelfth season of the American animated television series The Simpsons. The 257th episode overall, it originally aired on the Fox network in the United States on January 7, 2001. In the episode, while working as a human guinea pig, Homer discovers the root cause of his subnormal intelligence: a crayon that was lodged in his brain ever since he was six years old. He decides to have it removed to increase his IQ, but soon learns that being intelligent is not always the same as being happy.

The twelfth season of the American animated television series The Simpsons originally aired between November 2000 and May 2001. It began on Wednesday, November 1, 2000 with "Treehouse of Horror XI". The season contains four hold-over episodes from the season 11 (BABF) production line. The showrunner for the twelfth production season was Mike Scully. The season won and was nominated for numerous awards including two Primetime Emmy Awards wins and an Annie Award. Season 12 was released on DVD in Region 1 on August 18, 2009, Region 2 on September 28, 2009, and Region 4 on September 2, 2009.