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.

He finished 40th at the 2004 Olympic Games, and 5th at the 2005 World Championships.

In 2007 he won the Lake Biwa Marathon and competed at the 2007 World Championships in Osaka finishing 25th.

This biographical article relating to Tanzanian athletics is a stub.