Geneva English School was founded in 1961 by a small group of parents who wanted a British education for their children. A church hall at 14 rue Baulacre in Geneva was rented, a teacher was hired and the school started to grow.
By 1963, the number of pupils had expanded to 40 and the school relocated to larger premises at the Ecole Migros in rue du Prince. With demand for places continuing to grow, the school moved to a large house at 39 bis route de Malagnou and then, in 1967, to empty village school premises in Vésenaz.
In 1972, Denis Unsworth was appointed as Head. He stayed until retirement in 2007. A long and difficult search for new premises in the early 1980s eventually led to the identification of the magnificent ‘Petit Malagny’ site in Genthod, on the opposite side of the lake. In total, some six years were spent negotiating the final purchase, securing the loan, obtaining approval for the building's use as a school, agreeing plans for refurbishment and additional buildings and, finally, carrying out the building work. In 1989, the school moved to Genthod for the beginning of the summer term and was officially opened on Sports Day.
A fourth building opened in April 2013, providing a dining hall and dance studio in addition to the classrooms needed to facilitate an expansion to two classes per year group.
The most recent phase of development has seen the creation of GES Secondary in its new state-of-the-art facility in Versoix, just a few minutes from the primary site. From September 2017, the School has been accepting pupils into Year 7 (11+) and Year 8 (12+) and will grow organically, year on year, thereafter.