HistoryStockholm International School was founded in 1951, by Mrs. Gisela Dietze. Mrs. Dietze came to Stockholm from Dresden, Germany, shortly after the end of World War II, and began a private kindergarten among families associated with the British Embassy. This turned out to be quite popular, and eventually the British Council helped Mrs. Dietze to found the Anglo- American School, as it was then called.

The first school was located at Djurgårdsbrunns Värdshus, and it had 32 students. By the year's end it had 58 students, representing fifteen nations. The school grew steadily over time, and by 1967 it moved to its present location in the center of town, on Johannesgatan. Its student population then was 288.

Throughout this period, Mrs. Dietze remained as the Principal, and Stockholm International School had positioned itself as the preeminent English-speaking school in the Stockholm region. A true visionary, Mrs. Dietze was among the founding members of the European Council of International Schools (ECIS), and even from these early years, Stockholm International School has maintained an active role among international schools. The SIS has been accredited by ECIS since 1987, and is also accredited by the Middle States Association (since 1988), and the European League for Middle Level Education (since 1989). In addition, SIS has been host to a number of events, including the ELMLE Conference in 1995 and 2002, the Nordic Network Conferences 2001, 2008, 2012 and 2016, and the ISTA Drama Festival 2002.

Change and growth continue. In recent years the SIS has expanded to include grades 10, 11, and 12. Moreover, the school adopted the MYP and IB Diploma programs, and the International Primary Curriculum for Grades Reception through five.

History Provided by Mr. Aaron Nussbaum