Samson Ramadhani Nyonyi (born 25 December 1982 in Singida) is a Tanzanian marathon runner. He was the gold medalist at the 2006 Commonwealth Games that took place in Melbourne, Australia with the result at 2:11:29. In 2003 he participated three marathons: He won the Beppu Oita Marathon, was fifth at the London Marathon (time 2:08:01, still his personal best) and was 15th at the World Championships in Paris. He finished 40th at the 2004 Olympic Games, and 5th at the 2005 World Championships.