A constituent college of the University of Cambridge, Selwyn takes its name from George Augustus Selwyn, who was the first Bishop of New Zealand (1841-68) and later Bishop of Lichfield (1868-78), and in whose memory the College was founded.
The distinctive red-brick Victorian Old Court is Tudor Gothic in style, much of it designed by architect Sir Arthur Blomfield. The Court comprises seven staircases (on which members of the College live and teach), as well as the Tower and Gateway, Master's Lodge, Chapel, and Dining Hall.

Building began in 1880 on six acres of farmland purchased from Corpus Christi College, and at the time a short walk away from the older University buildings in the centre of Cambridge. However, the Sidgwick site – which includes such major faculty buildings as History, English and Law – was created right next to Selwyn; and due to the steady growth of the University and its development of the West Cambridge site, Selwyn now stands at its geographical heart.

The College opened in time for the beginning of the academic year in 1882, when 28 undergraduates were admitted. The teaching staff comprised the Master, the Tutor and one non-resident lecturer.

Selwyn grew in size over the years and its site expanded in the late 1960s with the building of Cripps Court, thanks to the generosity of the Cripps Foundation. During 2012 work started on refurbishing Cripps Court, adding an additional floor, and making almost all bedrooms en-suite.