The Dictum of Kenilworth, issued on 31 October 1266, was a pronouncement designed to reconcile the rebels of the Second Barons' War with the royal government of England. After the baronial victory at the Battle of Lewes in 1264, Simon de Montfort took control of royal government, but at the Battle of Evesham the next year Montfort was killed, and King Henry III restored to power. A group of rebels held out in the stronghold of Kenilworth Castle, however, and their resistance proved difficult to crush.

The Second Barons' War (1264–1267) was a civil war in England between the forces of a number of barons led by Simon de Montfort against the royalist forces of King Henry III, led initially by the king himself and later by his son, the future King Edward I. The barons sought to force the king to rule with a council of barons, rather than through his favourites. The war also involved a series of massacres of Jews by de Montfort's supporters, including his sons Henry and Simon, in attacks aimed at seizing and destroying evidence of baronial debts. To bolster the initial success of his baronial regime, de Montfort sought to broaden the social foundations of parliament by extending the franchise to the commons for the first time. However, after a rule of just over a year, de Montfort was killed by forces loyal to the king at the Battle of Evesham.