Founded by King Chulalongkorn in 1882 as a peer's school, its purpose was to educate the children of nobility and the royal household.

The school was established by King Chulalongkorn on 29 August 1882 and was originally for Royal Page Lieutenants.

Under the patronage and guidance of King Chulalongkorn the school grew quickly, changing its focus from military training to a more broadly-based curriculum that reflected the needs of its students.

It is thought to house the protective spirit of the place (known as "Grandfather"), with students making daily offerings of flower garlands as a token of respect.

For over a century, Suankularb's alumni have played important social, political, governmental, military, and academic roles in Thailand.

[citation needed] During its early days, English expatriates served as the board of directors, and made it possible for notable school leavers, such as MR Kukrit Pramoj, to continue their studies abroad at institutions such as Oxford University.

Every year on 29 August – the founding day of the school – all O.S.K ("Old Suankularb") students assemble in front of Building Six where they pay respects to the large statue of King Rama V there.

The school possesses an extensive library, with some rare and valuable books donated by former Prime Minister Thanin Kraivixien.