SSIS was founded in 1996 with 27 students. The school initially offered the Singaporean curriculum, before becoming an IB World School in 2001. SSIS gained authorization from the International Baccalaureate Organisation for the Middle Years Programme in 2001, Diploma Programme in 2003 and the Primary Years Programme in 2008.
In 2005 the first students graduated from SSIS. The same year the school moved to a purpose built campus located on Zhong Nan Jie, featuring modern facilities for teaching, sport, performing and visual arts.
In 2008 SSIS gained joint accreditation with the European based Council of International Schools, the New England Association of Schools and Colleges (US), and the National Centre for Curriculum and Textbooks (China).
In 2013, SSIS became one of the first schools in the world to successfully undertake a joint reaccreditation and evaluation process with the International Baccalaureate Organisation, the Council of International Schools, the New England Association of Schools and Colleges, and the National Centre for Curriculum and Textbooks simultaneously. At the end of this process, the school received 34 commendations and was described by the accreditation team as "a reflective institution committed to promoting internationalism and quality educational experiences, which has made impressive progress and meets the needs of its student body while building trust, communication and support with faculty and parents"
In 2016/17, SSIS is celebrating its 20th anniversary.