Marc Houtzager (born January 9, 1971 in Rouveen) is a Dutch show jumper.
Houtzager competed in the 2002 Show Jumping World Cup circuit and won the meeting in Dublin. After that he kept on riding international tournaments, but never succeeded on World Cup level again. In 2008 he and his team mates became Dutch national champion in Mierlo. Houtzager himself won an additional silver medal at the event in the individual competition. He was selected to represent the Netherlands at the Super League meeting in Rome where they finished fourth. At the CHIO in Rotterdam he became fifth in the individual competition. Later that year he finished fourth at the Grand Prix in Aachen with his horse Opium.
Due to injuries of former Olympic champion Jeroen Dubbeldam and Albert Zoer he and Angelique Hoorn were selected by coach Rob Ehrens to represent the Netherlands at the 2008 Summer Olympics in Beijing. Houtzager and Hoorn will compete in both the individual as well as the team competition in which they form a team with Gerco Schröder and Vincent Voorn.