It is said that respect is earned, while excellence is achieved.

The Overseas School of Colombo (OSC) has once again demonstrated why it is Sri Lanka’s leading international school, following a successful tri-agency accreditation involving the International Baccalaureate (IB), the Council of International Schools (CIS), and the Middle States Association of Colleges and Schools (MSA).

This joint visit resulted in a powerful endorsement from all three global accrediting bodies a testament to OSC’s consistent commitment to excellence, innovation, and continuous improvement. Uniquely, OSC remains the only dually accredited (CIS/MSA) international school in Sri Lanka.

While CIS and MSA are independent organisations, their evaluation was conducted as a unified team. The CIS/MSA findings reflect this seamless partnership.

OSC’s accreditation journey dates back to 1990 for CIS/MSA and to 1983 for the IB Diploma Programme. The school later added the IB Middle Years Programme in 1999 and the Primary Years Programme in 2002 – affirming its commitment to a rigorous, inquiry-driven curriculum.

The IB is a Geneva-based foundation promoting global mindedness and critical thinking through its internationally recognisedprogrammes. CIS, headquartered in the Netherlands, accredits schools focused on intercultural learning, well-being, and ethical leadership. MSA, one of the oldest U.S. accreditation agencies, evaluates student outcomes and institutional integrity.

Over four days, 10 global evaluators engaged deeply with the OSC community. They encountered a school not just meeting benchmarks, but redefining them.

“OSC is an international school exemplar,” stated the CIS/MSA team. “It is more than an international IB school it is a community driven school with a strong sense of shared purpose.”

The IB praised OSC’s Teacher Growth and Improvement Framework, calling it “the best the IB has ever seen” describing it as “research-backed and comprehensive.”

Evaluators consistently highlighted OSC’s caring, inclusive culture and its focus on student agency and wellbeing. “Learning at OSC is dynamic,” noted the IB team, citing strong service learning opportunities. “Students explain their learning clearly,” added the CIS/MSA team a reflection of OSC’s student-centred approach.

Special recognition was given to Coert Van Zijl, OSC’s Internal Coordinator of Accreditation, for producing a self-study described as a “model example” for other schools.

Head of School Dr Michelle Kleiss attributed this success to the strength of the school’s academic leadership, professional learning culture, seamless operations, and the active participation of students, faculty, and families.

For families exploring international education in Sri Lanka, this tri agency validation affirms OSC’s trustworthiness and leadership. “OSC has positive community impact your parents are happy, and they know they can come in and be heard,” one CIS/MSA evaluator concluded.

In a world seeking schools that inspire trust and deliver lasting impact, OSC stands out not just in Sri Lanka, but globally.