Due to the foresight of Lord Delamere in proposing the building of a senior Boys school (now Nairobi Primary), and the support of the then Governor, Sir Edward Grigg, the railway reserve grounds near Kabete were set aside for future use.

On 24 September 1929 the foundation stone was laid by Sir Edward Grigg, Governor of Kenya colony, for a school with a capacity of 80 boys.

The effects of the war were felt more when the Italians joined in June 1940, including the fear of bombing, and it was made a day school.

Nairobi School sits on over 80 ha (200 acres) of land about 11 kilometres from the city centre and has over 1100 students currently enrolled.

[2] Nairobi School had a cadet training course of paramilitary standard in which students could enrol.

After the colonial era Kenya Regiment, the school continued with the cadet course until stopped by the government after the unsuccessful 1982 coup d'état.

The cadet section had uniforms, guns, ammunition, an armoury, a parade ground with adjacent stores and offices and a shooting range.

The houses serve as dormitories, as well as for student organisation for the purpose of sports days, dining hall seating and school assembly.

Students develop strong links with members of their house, and these become evident on sports days as well as in academics.

The houses are: The name changes, reflecting geographical areas in Kenya, were adopted in 1975 as part of a deliberate policy of Africanisation.

The administration block was used as the setting for the Government House in the Oscar-winning movie Out of Africa, based on a book with the same title by the Danish writer Karen Blixen.