Ruamrudee International School (RIS)

Ruamrudee, almost always referred to as RIS, is one of Bangkok's oldest American curriculum schools, founded the same year as Bangkok Patana in 1957, and has grown into one of the largest international schools in the city by enrollment. It offers a genuinely broad range of pathways, including an American diploma track, AP courses, and the IB Diploma Programme as an option in the final two years.

The main campus is large enough to support both a full American-style athletics and activities program and a separate Swiss Section teaching a German-language curriculum for German-speaking families, an unusual combination that reflects how large and diverse the school's population has become over nearly seven decades.

RIS is a member of IASAS, competing directly against ISB, Patana, NIST, and other major regional schools in sports and arts, which places it firmly among Bangkok's tier of large, well-resourced international schools rather than the city's smaller boutique options.

With such long history and scale, RIS tends to appeal to families who want an established, full-service American school with genuine choice in exam pathway, rather than a smaller or more specialized option.