Ong Keng Yong (born 1954) is a Singaporian diplomat. He has been the secretary-general of the Association of Southeast Asian Nations since January 6 2003.
Ong was educated at the University of Singapore and Georgetown University. He entered the Singaporian diplomatic service in 1984. For the next ten years he worked in Saudi Arabia, Malaysia and the United States successively at the Singaporian embassies in those countries. From 1994 to 1996 he was a foreign ministry spokesman. From 1996 to 1998 he was ambassador and high commissioner of Singapore to India and Nepal. From 1998 to 2002 he worked as an important aid to Prime Minister Goh Chok Tong, leaving that job late in 2002 when he was elected secretary-general of ASEAN.