The official admission register of The University School started in 1954 but it is almost certain that the school first opened one year before that. The School was formed to provide educational facilities for children of the senior staff of the Imperial College of Tropical Agriculture (ICTA). In the early years, the school was managed by an elected committee of the ICTA Senior Staff Association. By 1966, ICTA had been replaced by the Faculty of Agriculture of The University of the West Indies (UWI) and The University School Association Limited was formed in that year.
Although the School has maintained its primary objective to provide for the children of the academic staff of the St. Augustine Campus of The UWI, its nature and role have changed over the years. Whereas in the 1950s most of the senior staff of ICTA were expatriates from the U.K., the University staff now are predominantly nationals of Trinidad and Tobago with many of the non-national staff also being West Indian. Children of parents with origins outside the Caribbean continue to attend The University School, but these are now a minority. Besides children of the University staff, the school has always been able to make available places to the general public. The School is committed to maintaining diversity in its student population.