Magna Carta, also called Magna Carta Libertatum (the Great Charter of Freedoms), is an English legal charter, originally issued in the year 1215. It was written in Latin; its name is usually translated into English as Great Charter.

Magna Carta required King John of England to proclaim certain rights (pertaining to nobles and barons), respect certain legal procedures, and accept that his will could be bound by the law. It explicitly protected certain rights of the King's subjects, whether free or fettered — and implicitly supported what became the writ of habeas corpus, allowing appeal against unlawful imprisonment.

Magna Carta was arguably the most significant early influence on the extensive historical process that led to the rule of constitutional law today in the English speaking world. Magna Carta influenced the development of the common law and many constitutional documents, including the United States Constitution. Many clauses were renewed throughout the Middle Ages, and continued to be renewed as late as the 18th century. By the second half of the 19th century, however, most clauses in their original form had been repealed from English law.