Grégory Rast (born 17 January 1980 in Cham) is a Swiss former professional road bicycle racer, who rode professionally between 2001 and 2018 for the Post Swiss Team, Phonak, Astana, Team RadioShack and Trek–Segafredo teams. He was the winner of the Swiss National Road Race Championships in 2004 and 2006. Rast now works as a directeur sportif for the Trek–Segafredo team. His sporting career began with RMV Cham-Hagendorn.