The Great Quadrangle, more popularly known as Tom Quad, is one of the quadrangles of Christ Church, Oxford, England. It is the largest college quad in Oxford, measuring 264 by 261 feet. Although it was begun by Cardinal Wolsey, he was unable to complete it. Wolsey planned that it would actually be a cloister, and the supports required for this can be seen at short intervals around the quadrangle. The quad was finished when John Fell was Dean. The funds for the building of Tom Quad were found from the suppression of three Norbertine abbeys. It is dominated to the west by Tom Tower, designed by Sir Christopher Wren. On the east side is the entrance to Christ Church Cathedral and at the south-east corner is the entrance to the college dining hall. The north contains the homes of the canons of Christ Church, and much of the east side is taken up with the Deanery, in which the Dean of the college lives. On the north-east side, the quad leads, via Kilcannon, to Peckwater Quadrangle and the college library. In the north-west part of the quad is the Junior Common Room ("JCR"). Parts of the quad are still lived in by undergraduates, including the staircase above the Porter's lodge, known as "Bachelors' Row", to the left of the quadrangle when entered via Tom Gate. Bachelors' Row is only inhabited by first year male undergraduates.
In the centre of the quad, there is an ornamental pond with a statue of Mercury. In the past, it was traditional for "hearties" (sporty students) to throw "aesthetes" (more artistic students) into this pond. Currently, entrance to Mercury carries a heavy fine for undergraduates. The pond also contains a large Koi carp apparently worth a large amount of money and donated by the Empress of Japan. The base of the fountain was designed by Sir Edwin Lutyens.
- In a famous scene from Waugh's novel, aesthete Anthony Blanche is accosted by some sportsmen in the manner described above: "I got into the fountain and, you know, it really was most refreshing, so I sported there a little and struck some attitudes, until they turned about and walked sulkily home, and I heard Boy Mulcaster saying, ‘Anyway, we did put him in Mercury’. You know, Charles, that is just what they'll be saying in thirty years' time. When they're all married to scraggy little women like hens and have cretinous porcine sons like themselves getting drunk at the same club dinner in the same coloured coats, they'll still say when my name is mentioned 'We put him in Mercury one night,' and their barnyard daughters will snigger and think their father was quite a dog in his day, and what a pity he's grown so dull. Oh, la fatigue du Nord!" Brideshead Revisited, Evelyn Waugh (1945)