A royal charter is a formal grant issued by a monarch under royal prerogative as letters patent. Historically, they have been used to promulgate public laws, the most famous example being the English Magna Carta (great charter) of 1215, but since the 14th century have only been used in place of private acts to grant a right or power to an individual or a body corporate. They were, and are still, used to establish significant organisations such as boroughs (with municipal charters), universities and learned societies.

Charters should be distinguished from royal warrants of appointment, grants of arms and other forms of letters patent, such as those granting an organisation the right to use the word "royal" in their name or granting city status, which do not have legislative effect. The British monarchy has issued over 1,000 royal charters. Of these about 750 remain in existence.

The earliest charter recorded on the UK government's list was granted to the University of Cambridge by Henry III of England in 1231, although older charters are known to have existed including to the Worshipful Company of Weavers in England in 1150 and to the town of Tain in Scotland in 1066. Charters continue to be issued by the British Crown, a recent example being that awarded to The Chartered Institute of Ergonomics and Human Factors, in 2014.