The International School Ibadan (ISI) is located on the Campus of the University of Ibadan, Nigeria's oldest university. It was founded on 13th October 1963 as a joint project between the Ford Foundation and the University. It is a co-educational Boarding and Day School admitting pupils aged 9 to 19. It was primarily established to meet the need of finding a school with a standard comparable to schools in Europe and America for children of expatriates, living and working in Nigeria. It opened its doors to pupils of both expatriates and highly placed Nigerians. The social setting that ISI provided attracted more patronage from people of all races.
The first principal was Mr. S.D. Snell; followed by Mr. Gillespie. The longest serving principal was an anglican clergy, Archdeacon J.A.Iluyomade. He was also the first indigenous head of the school. After him was Rev. (Dr.) Dapo Ajayi, then Mr. Dapo Fajembola. Thereafter came the first female principal, Mrs. Esther Smith. After her was Mr. R.O. Akintilebo. The present principal (as at 2012) is Mr. M.B Malik.
I.S.I is well known for socials, extra-curricular activities like the International soiree (an event which comes up once every two years). The International soiree is an evening where all the nationalities represented among staff and students display the food, clothing and other material aspects of culture for sale with the objective of raising money for the less privileged. The Charity walk is another event that students use to raise money for the less privileged. Service to mankind is embedded in the culture of ISI. This tradition continues till this day. The school song goes thus:
"These things shall be, a new generation, in every land, of boys and girls shall stand, for brotherhood of man, and service to mankind, and love for truth and peace, From ISI with one acclaim we pledge, our faith in thee ....ISI!"
Academically,it originally followed the British system of five years to preparation for Ordinary Level (General Certificate of Education) and West African School Certificate Examinations; with another two years in the sixth form to prepare for Advanced level (General Certificate of Education) and Higher School Certificate examinations. However, the introduction of the 6-3-3-4 system of Nigerian education introduced in the late eighties, it runs the mandatory six years of secondary school education, in addition to preparing students for international exams like the annual London GCE 'O' and 'A' level exams. It also for many years has offered preparation for the International Baccalaureate Examination. Although it now follows the 6-3-3-4 system of Nigerian education, many of the students continue to prepare for international exams. The 'A' Level programme was recently resuscitated in September 2011.
ISI has produced notable graduates among whom are Late Gbegi Ojora (a leading industrialist and socialite), Professor Fagbemi (a leading academic/veterinary scientist), Ngozi Okonjo-Iweala (Nigerian former Finance Minister and world bank economist), Helen Prest Ajayi (Miss Nigeria 1979), Glenn Inanga (pianist), Ifedayo Olarinde (D.J. Freeze of Cool F.M), Najite Dede and Michelle Dede (Nigerian entertainers), Adeboye O. Osunkoya, MD (Urologic Pathologist, Emory, USA), Pastor Jide Odulami (of RCCG Jesus House, Port Harcourt, Nigeria) Pastor Idowu Iluyomade (RCCG, House of David, Lagos), Opeyemi Ajaiyeoba (Engr.) and a whole lot of others.