Ieng Sary (Khmer: ??? ????; 24 October 1925 – 19 March 2013) was a co-founder and senior member of the Khmer Rouge.
He was a member of the Central Committee of the Communist Party of Kampuchea led by Pol Pot and served in the 1975–79 government of Democratic Kampuchea as foreign minister and deputy prime minister.
He was known as "Brother Number Three" as he was third in command after Pol Pot and Nuon Chea.
Ieng Sary was arrested in 2007 and was charged with crimes against humanity but died of heart failure before the case against him could be brought to a verdict.