Edward III (13 November 1312 – 21 June 1377) was king of England from 1327 until his death and is noted for his military success. Restoring royal authority after the disastrous reign of his father, Edward II, Edward III went on to transform the Kingdom of England into one of the most formidable military powers in Europe. His reign saw vital developments in legislation and government – in particular the evolution of the English parliament – as well as the ravages of the Black Death. He remains one of only five monarchs to have ruled England or its successor kingdoms for more than fifty years.

Edward was crowned at the age of fourteen, following the deposition of his father. When he was only seventeen years old, he led a coup against the de facto ruler of the country, his mother's consort Roger Mortimer, and began his personal reign. After a successful campaign in Scotland in 1333, he declared himself rightful heir to the French throne in 1337, starting what would become known as the Hundred Years' War. Following some initial setbacks, the war went exceptionally well for England; the victories of Crécy and Poitiers led to the highly favourable Treaty of Brétigny. Edward's later years, however, were marked by international failure and domestic strife, largely as a result of his inactivity and bad health.

Edward III was a temperamental man, but also capable of unusual clemency. He was in many ways a conventional king, whose main interest was warfare. Admired in his own time and for centuries after, Edward was denounced as an irresponsible adventurer by later Whig historians such as William Stubbs. This view has been challenged recently, and modern historiography credits him with some significant achievements.