It was founded in February 1943 by Father Alan Rogers in his study at the parsonage of St Paul's, Vacoas, under the blessing of Bishop Hugh Otter-Barry.

The next year in March 1944 the school moved to St Paul's Theological College opposite the present location in Ambrose Street, Rose Hill.

On 15 June 1950, the St Andrew's College Foundation was established by Ordinance No.30 of 1950 on the wish of Dr the Honourable Edgar Laurent, C.M.G., M.D., Lic-ès-Sc.

In June 1961, in her Birthday Honours list, H.M. the Queen conferred the OBE on Canon McAvan in recognition of his devoted service to the cause of education.

Ham Koung [John] Ng Lung Kit became the first laureate (Science side) of St Andrew's in February 1972; he later obtained his FRCS from Edinburgh Royal College of Surgeons and is today Managing Director of Clinique Mauricienne.)

In May 1984, Donat vacated his post to become Bishop of Mauritius and was succeeded by Mr Donald Runghen, B.A., P.G.C.E., as rector since the title of Warden was phased out.