Marcus "Mark" Tewksbury, (born February 7, 1968 in Calgary, Alberta, Canada) is a Canadian former swimmer. He is best known for winning the gold medal in the 100 metres backstroke at the 1992 Summer Olympics. He also hosted the first season of How It's Made, a Canadian documentary series, in 2001. Tewksbury was awarded the Meritorious Service Medal (Civil Division) in 1993 for being a "motivational speaker and a gifted athlete."