The Interscholastic Association of Southeast Asian Schools (IASAS) is an association of six private schools in and around Southeast Asia. The member schools are International School Bangkok (Thailand), International School of Kuala Lumpur (Malaysia), International School Manila (Philippines), Jakarta Intercultural School (Indonesia), Singapore American School (Singapore), and Taipei American School (Taiwan).
High-level competitions and events involving teams or groups from the IASAS schools are held throughout the school year in areas of sports, or cultural and artistic events. Sports competitions are organized into three separate seasons, and tournaments are held at the end of approximately 10-week seasons. Cultural and Artistic events are held in separate seasons from sports, with Model United Nations during one season (non-competitive event), and the Arts events during another season. Each of the IASAS schools rotate the hosting of events, based on available facilities and current events of each country. While participating in events, students are expected to adhere to a strict code of conduct. Students traveling to other schools to participate in IASAS events stay with families of students from the host school. The events, organized by season, are listed below.
The first season of IASAS, held in October, includes soccer, volleyball, and cross country running. The second season of IASAS, held in February, includes basketball, rugby union (for men), touch rugby (for women), swimming, and tennis. The third season of IASAS, held in April, includes badminton, fastpitch softball (for women) and baseball (for men), golf, and track and field. In addition to the culminating IASAS events that occur at the end of each season, athletics exchanges are held during the season so that teams have an opportunity to see the competition from the other schools. These exchanges usually only involve three or four of the IASAS schools at a time, and no awards are given for winning an exchange. In fall 2019, International School of Manila held a 'Super IASAS', with all season one sports occurring in the same location. In the 2020-21 and the 2021-22 academic year, no in-person IASAS events were held in light of the ongoing effects of the COVID-19 pandemic.
The Leadership Convention, a conference for student peer-helper groups took place in September 2005, 2006, and 2007, but was discontinued during the 2008-2009 academic year due to the effort to reduce unnecessary travel for non-competitive events. Model United Nations is held in November, usually with additional schools participating.
Cultural Convention (CC) is held in March and includes three separate events: "Music", "Dance, Drama, Art and Theatre Tech (Stagecraft)", and "Debate and Forensics". The music delegation includes choir, strings, band and pianists. Forensics events include Original Oratory, Oral Interpretation, Extemporaneous Speaking, and Impromptu. While the first IASAS CC combined all events into a single convention, in the modern CC the three components take place concurrently but are typically hosted in different schools.