Yusuf Saad Kamel (Arabic: يوسف سعد كامل), born Gregory Konchellah (born March 29, 1983), was the 2009 world champion at 1500 meters, representing Bahrain after his switch from Kenya. He specializes in the 1500 metres and 800 metres. He was born in Narok, Kenya.
In 2009 he stopped competing for Bahrain claiming unpaid salary and bonuses. He was willing to compete for Kenya, but his Kenyan passport is held by Bahraini officials. Without a passport, he was unable to compete in any competition. Several other Kenyan runners who took Bahraini citizenship have also left Bahrain and are vying to compete for Kenya. However, he returned to the track in July 2009 at the Athletissima meeting, still representing Bahrain. Subsequently, Athletics Kenya stopped to handle his attempt to compete for Kenya.