Tough Guy Challenge is an annual racing event to raise cash for charity by challenging thousands of international competitors in a cross country run followed by an assault course consisting of obstacles including water, fire and tunnels. First staged in 1987 in England, the Tough Guy Challenge has been widely described as the world's most demanding one-day survival ordeal.

Taking place at the end of January, often in freezing winter conditions, the Tough Guy race is staged over a course of between seven and eight miles (about 12 kilometers). It starts with a cross-country run which is followed by one of the world's toughest assault courses, featuring 25 obstacles, including a slalom run up and down a hill, ditches, jumps, freezing water pools, and fire pits. Organized by Billy Wilson with the pseudonym "Mr. Mouse", the Tough Guy Challenge claims that running the course involves risking barbed wire, cuts, scrapes, burns, dehydration, hypothermia, acrophobia, claustrophobia, electric shocks, sprains, twists, joint dislocation and broken bones.

After 27 stagings of the winter event, Wilson still claimed nobody had ever finished the course according to his extremely demanding rules. The race, and its summer equivalent, has suffered two fatalities during its history.