Prasong Soonsiri is a Thai politician, and former Royal Thai Air Force squadron leader, Thai Foreign Minister, and head of the Thai National Security Council. Prasong has been a long-time critic of Thaksin Shinawatra since Thaksin's entry into politics in 1994. Thaksin joined the Palang Dharma Party in late 1994 under the invitation of Chamlong Srimuang, who had just reclaimed the position of party leader from Boonchu Rojanastien. In a subsequent purge of Boonchu-affiliated PDP Cabinet ministers, Thaksin was appointed Foreign Minister, replacing Prasong Soonsiri.
Prasong was a central figure in the 19 September 2006 Thai military coup that overthrew Thaksin Shinawatra's elected government. Prasong had developed plans for a military coup as early as July 2006. A palace insider and favorite of King Bhumibol Adulyadej, Prasong was later appointed by the junta to the National Legislative Assembly.