Montessori kindergartens are common across Hong Kong but there is only one primary school using the internationally adopted teaching approach.
The International Montessori School in Tin Hau recently became only the second accredited primary school in Asia. The other one is in Japan.
IMS was accredited by the US-based International Montessori Council after an inspection by a four-member panel in October.
The government had previously planned to turn the school site into a youth hostel but dropped the plan following public opposition.
The inspection covered about 125 standards and criteria, including the educational programmes, student-teacher ratios, teacher qualifications, curriculum, group size and facilities, among others.
With 600 pupils, IMC advocates bilingualism and has developed its own Chinese curriculum materials incorporating the Montessori philosophy, which dates to the early 20th century, when Italian educator and scientist Maria Montessori developed the approach based on her own research that showed children learn best by doing, not by passively accepting knowledge.
The inquiry-based approach has gained popularity in recent decades. Montessori primary schools are fast expanding in China and around the world, according to IMS co-founder Karin Ann. She set up the school a decade ago with Anne Sawyer to provide the education they wanted for their children.
"Many students go to International Baccalaureate schools as they share a similar philosophy, in terms of having a holistic way of educating their children: what is my place in the world? How do things inter-connect? How do I be a part of it?" Ann said.
Creative minds such as Google founders Larry Page and Sergey Brin, and Amazon founder Jeff Bezos, have credited their thinking and problem-solving skills to their Montessori education, the founders said.
"What Montessori did is create a very structured environment that enables each child to go through the curriculum, but in a way most likely to meet their desire for motivation," Sawyer said.
She says she sees Hong Kong as an important hub for Montessori education.
"The accreditation sends a strong message that Hong Kong has a broad quality range of international schools."