In 1926, Sister Marie Bernard Mancel, the second superior of the Ursuline Order in Thailand, decided to purchase a piece of land of about 18 rai (just under 3 hectares) with a large house.

The Ministry opened a Pre-University School in order to prepare students for university education.

It ordered other schools to discontinue classes for the last two years in the Secondary level, thus reducing the student numbers.

There was no emphasis on vocational training, but students were taught domestic science and job skills.

It was moved back to the original location in 1945 when the war ended and the Japanese occupiers left.

In 1960 the Sisters built a new school at Lang Suan Road for their growing student body.

At Upper Secondary level, students can pick one out of three curriculums: Science, Art, and French.