Succession to the British throne is determined by descent, sex, legitimacy, and religion. Under common law, the Crown is inherited by a sovereign's children or by a childless sovereign's nearest collateral line. The Bill of Rights 1689 and the Act of Settlement 1701 restrict succession to the throne to the legitimate Protestant descendants of Sophia of Hanover who are in "communion with the Church of England". Spouses of Catholics were disqualified from 1689 until the law was amended in 2015. Protestant descendants of those excluded for being Roman Catholics are eligible.

The Act of Settlement is an Act of the Parliament of England that settled the succession to the English and Irish crowns to only Protestants, which passed in 1701. More specifically, anyone who became a Roman Catholic, or who married one, became disqualified to inherit the throne. This had the effect of deposing the remaining descendants of Charles I, other than his Protestant granddaughter Anne, as the next Protestant in line to the throne was Sophia of Hanover. Born into the House of Wittelsbach, she was a granddaughter of James VI and I from his most junior surviving line, with the crowns descending only to her non-Catholic heirs. Sophia died shortly before the death of Queen Anne, and Sophia's son succeeded to the throne as King George I, starting the Hanoverian dynasty in Britain.