A draft horse (US), draught horse (UK) or dray horse (from the Old English dragan meaning to draw or haul; compare Dutch dragen meaning to carry), less often called a work horse or heavy horse, is a large horse bred for hard, heavy tasks such as ploughing and farm labor. There are a number of different 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, show, 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. While most draft horses are used for driving, they can be ridden and some of the lighter draft breeds are capable performers under saddle.

Draft horses are recognizable by their tall stature and extremely muscular build. In general, they tend to have a more upright shoulder, producing more upright movement and conformation that is well-suited for pulling. They tend to have broad, short backs with powerful hindquarters, again best suited for the purpose of pulling. Additionally, the draft breeds usually have heavy bone, and a good deal of feathering on their lower legs. Many have a straight profile or "Roman nose" (a convex profile). Draft breeds range from approximately 16 to 19 hands high and from 1,400 to 2,000 lb (640 to 910 kg).