The 1648 Second English Civil War was part of a series of connected conflicts in the British Isles, incorporating England,Wales, Scotland, and Ireland. Known collectively as the 1638 to 1651 Wars of the Three Kingdoms, others include the Irish Confederate Wars, the 1638 to 1640 Bishops' Wars, and the Cromwellian conquest of Ireland.

Following his defeat in the First English Civil War, in May 1646 Charles I surrendered to the Scots Covenanters, rather than Parliament. By doing so, he hoped to exploit divisions between English and Scots Presbyterians, and English Independents. At this stage, all parties expected Charles to continue as king which combined with their internal divisions allowed him to refuse significant concessions. When the Presbyterian majority in Parliament failed to dissolve the New Model Army in late 1647, many joined with the Scottish Engagers in an agreement to restore Charles to the English throne.

The Scottish invasion was supported by Royalist risings in South Wales, Kent, Essex and Lancashire, along with sections of the Royal Navy. However, these were poorly co-ordinated and by the end of August 1648, they had been defeated by forces under Oliver Cromwell and Sir Thomas Fairfax. This led to the Execution of Charles I in January 1649 and establishment of the Commonwealth of England, after which the Covenanters crowned his son Charles II king of Scotland, leading to the 1650 to 1652 Anglo-Scottish War.