Beginning in 1985, at the initiative of former Chinese Premier Zhao Ziyang, who visited Sidwell in 1984, Sidwell Friends began its long and productive relationship with its sister schools in China. In that year Sidwell Friends began hosting two students from High School No. 2 Attached to Beijing Normal University. Later, Sidwell Friends began a sister school relationship with the High School Affiliated to Fudan University in Shanghai. Presently, one student from each of these sister schools comes to Sidwell each year. The students stay with Sidwell families, take a range of courses, and participate in the greater life of the school.
Beginning in the 2005-06 academic year, Sidwell Friends initiated a teacher exchange program with its sister schools. Every other year a discipline is jointly chosen by Sidwell and its sister schools, and teachers from that discipline participate in the exchange. Through this exchange, teachers on both sides gain greater awareness and knowledge of both pedagogy and cultural issues related to that discipline.