The school's buildings lie in grounds which face open country on the edge of Warminster town centre.

In 1707, Thomas Thynne, 1st Viscount Weymouth, under the influence of Bishop Thomas Ken (1637–1711), founded a grammar school for boys in the market town of Warminster, near to his family seat of Longleat, to instruct the boys of Warminster, Longbridge Deverill, and Monkton Deverill in Latin, mathematics, and other subjects of the usual syllabus of the day.

In 1673 he married Lady Francis Finch, a daughter of the Earl of Winchelsea, and lived at Drayton Basset, near Tamworth.

While Henry Dison Gabell was its schoolmaster, from 1790 to 1793, he had twenty boys to teach on the foundation, for which he was paid £30 a year, but had the right to supplement this by taking private pupils.

The original intention was to train boys and young men who had little previous education but were capable of becoming good workers.

In 1890 the students built themselves a cricket pavilion and established a printing press, on which they were publishing a college magazine in 1896.

[citation needed] In 1897 the foundation stone of new permanent buildings was laid on the north side of the house.

In 1913, after the death of Philipps, the constitution of the College was changed and one of the purposes now listed was for the actual training of missionaries.

In 1927, a large extension to the south, designed by Sir Charles Nicholson, added a chapel and library.

In 1943, J. W. Tomlin, the former Principal of the College, wrote of St Boniface that, even if it should be called upon to fulfil a different role in the future, it may well be that "the latter glory of the house shall be greater than the former".

[6] In September 1996, the St Denys building re-opened as a boarding house of Warminster School, for senior boys from Year 9 to the Upper Sixth.