A draft horse (US), draught horse (UK) or dray horse (from the Old English dragan meaning "to draw or haul"; compare Dutch dragen and German tragen meaning "to carry" and Danish drage meaning "to draw" or "to fare"), less often called a carthorse, work horse or heavy horse, is a large horse bred to be a working animal doing hard tasks such as plowing and other farm labor. There are a number of breeds, with varying characteristics, but all share common traits of strength, patience, and a docile temperament which made them indispensable to generations of pre-industrial farmers.

Draft horses and draft crossbreds are versatile breeds used today for a multitude of purposes, including farming, draft horse showing, logging, recreation, and other uses. They are also commonly used for crossbreeding, especially to light riding breeds such as the Thoroughbred, for the purpose of creating sport horses of warmblood type. While most draft horses are used for driving, they can be ridden and some of the lighter draft breeds are capable performers under saddle.