Off-road triathlon is a form of triathlon, or three-stage race, consisting of a swim stage, mountain-biking stage, and a trail-running stage.

Off-road triathlons are distinguished from conventional triathlons in that the terrain for the cycling and running stages are generally unpaved, rough, and very steep and hilly. They require different techniques than conventional triathlon races, and in particular the athletes employ mountain bikes rather than road bikes.

The XTERRA is the best-known series and championship of off-road triathlons, though many others exist.

Multi-sport competitions | Triathlon