Ong Jian Guo (born 29 January 1989 in Malacca) is a badminton player from Malaysia. Ong was selected to join the Malacca team in 2001, and two years later he moved to Kuala Lumpur to be educated at the Bukit Jalil Sports School. He was the bronze medalist at the 2007 World Junior Championships in the boys' doubles event, and helped the Malaysia men's team won the silver medal at the 2011 Southeast Asian Games in Jakarta, Indonesia.