Cover of the first edition, published by Simon & Schuster.

Sin Killer is a historical novel by American writer Larry McMurtry. It is the first, both in chronological and publishing order, of The Berrybender Narratives. Set in 1832, it follows the adventures of a clan of eccentric British aristocrats and their retainers as they begin a hunting expedition up the Missouri River.

The title refers to the nickname given to frontiersman Jim Snow, a Berrybender ally who violently hates sin of all kinds.