The S. Rajaratnam School of International Studies (RSIS) is an autonomous graduate school of Nanyang Technological University (NTU) and a defence and security-oriented think tank in Singapore. Founded in 1996 as the Institute of Defence and Strategic Studies (IDSS), RSIS offers graduate education in international affairs and strategic studies, taught by an array of international faculty. The school is named in honour of S. Rajaratnam, Singapore's former deputy prime minister who had also been its longest-serving Foreign Minister. It is regarded as one of the best graduate schools for international studies in Asia.