Reanchai Seeharwong (born 24 March 1976 in Samut Prakan) is a retired Thai sprinter who specialized in the 100 and 200 metres. He won the bronze medal in the 200 metres at the 1994 Asian Junior Championships. He won the 100 and 200 metres back to back at both the 1995, 1999 and 2001 South East Asian Games. His breakthrough came at the 1998 Asian Games where he won the silver medal in the 100 metres as well as another silver in the 4 × 100 metres relay.