Mob Quad is a four-sided group of buildings from the 13th and 14th centuries in Merton College, Oxford, surrounding a small lawn. It is often claimed to be the oldest quadrangle in Oxford and elsewhere, although Merton's own Front Quad was actually enclosed earlier and Corpus Christi College, Cambridge, says that its own Old Court is the oldest structure of its type in either Oxford or Cambridge. The quadrangle pattern has since been copied at many other colleges and universities worldwide.

Merton College is one of the constituent colleges of the University of Oxford in England. Its foundation can be traced back to the 1260s when Walter de Merton, chancellor to Henry III and later to Edward I, first drew up statutes for an independent academic community and established endowments to support it. An important feature of de Merton's foundation was that this "college" was to be self-governing and the endowments were directly vested in the Warden and Fellows.