Royal College, Colombo also known as; Royal Colombo, Colombo Royal College or Colombo Royal is a boys' school located in Cinnamon Gardens, Colombo, Sri Lanka. Started by Joseph Marsh in 1835, it was established as the Colombo Academy by Sir Robert Wilmot-Horton in January 1835, as part of the implementation of the recommendations of the Colebrooke Cameron Commission (1833), and was the first government-run secondary school for boys in the country.

Royal College is the first public school in Sri Lanka and is often referred to as the "Eton of Sri Lanka". The school was founded in the British public school tradition, based on the recommendations of the Colebrooke Cameron Commission (1833), and having been named the Royal College, Colombo in 1881 with consent from Queen Victoria, it became the first school to gain the prefix, "Royal", outside of the British Isles. It was one of the first schools to be designated as a national school by the Sri Lankan Government in the 1980s.

As a national school, it is funded by the government as opposed to the provincial council providing both primary and secondary education. The school was set as one of the most innovative educational institutions in the world at the fifth annual Worldwide Innovative Education Forum (IEF), organised by the Microsoft Corporation in 2009.

The students of Royal College are known as Royalists or referred to in the press as Colombo Royalists. whilst past pupils are known as Old Royalists. The school has produced many distinguished alumni, among whom are presidents of two countries, a sultan, and four prime ministers.

Situated in Cinnamon Gardens belonging to Kurunduwatta (also called Kurundu Watta), a residential suburb of Colombo, it occupies an area of 15.6 hectares (39 acres) (with the sports complex) along the Rajakeeya Mawatha, bordered by Reid Avenue to the east; Kumarathunga Munidasa Mawatha (formally Thurstan Road) to the west and to the south its former premises, which now houses the Department of Mathematics of the University of Colombo. Adjacent to Royal College is Thurstan College (formerly the Government Senior School), which was established to accommodate the overflow of students from Royal Primary who could not gain admission to Royal College.

The college is funded by the Ministry of Education, which appoints its principal. The principal is the head of the administration of the college and is assisted by a Senior Deputy Principal. The school is divided into four sections: the primary school (the former Royal College Preparatory School), middle school, upper-middle school and the upper school, each coming under a deputy principal (the head of the primary school is known as the headmaster/headmistress). The college educates close to 9,000 students in both secondary and primary education. The administration of the college hostel is carried out by the warden under the supervision of the principal and is assisted by a sub-warden.

The senior prefects of the school also hold comparatively an important role in the school. Since they have completed their final examinations, they are senior to any other student of the college. Hence their disciplinary powers extend to all students of Royal College.

Admission to the school is among the most competitive in the country. It gets its highest number of applications for admission to grade 1 and the best 250 students from all over the country to enter the school in year 5 via the grade 5 scholarship examination.