The origins of SGIS can be traced back to Lugano, October 1966, where only the second-ever Autumn Conference of the European Council of International Schools (ECIS) was held at Villa Negroni, the home of the The American School in Switzerland (TASIS). ECIS had been founded only the previous year, following a meeting at The College du Leman (CDL) in March 1965.
Following the Lugano conference, informal soundings were made through 1967 and 1968 with the idea of linking international schools in Switzerland.
Eventually a working party met at Institut Le Rosey, Rolle, in the spring of 1969, with the mandate of drawing up a set of statutes. The working party comprised of Brian Bissell (Commonwealth American School, Lausanne); Terry Gale (CDL); Mike Hope (Lycée des Nations) and the Headmaster of the host school, Malcolm Whitehead.
The first formal gathering of lectures and workshops, chaired by Brian Bissell, took place at The English Speaking School of Berne (now the International School of Berne), in October 1969 when forty delegates attended.
Each year, following its foundation, SGIS provided subject-specific workshops for teachers; and comprehensive sports events for students.
In 1989 a two-day conference was held in Thun, with the renowned anthropologist Jane Goodall, as the keynote speaker. This was deemed such a success, that an annual two-day conference has been held each year ever since, attracting around three hundred educators from the member schools.