Prince William Frederick, Duke of Gloucester and Edinburgh KG GCB GCH PC FRS (15 January 1776 – 30 November 1834), was a great-grandson of King George II and nephew and son-in-law of King George III of the United Kingdom.

Prince William was born on 15 January 1776 at Palazzo Teodoli in via del Corso, Rome. His father was Prince William, Duke of Gloucester and Edinburgh, the third son of the Prince of Wales. His mother was Maria, Duchess of Gloucester and Edinburgh, the illegitimate daughter of Edward Walpole and granddaughter of Robert Walpole. As a great-grandson of George II he held the title of Prince of Great Britain with the style His Highness, not His Royal Highness, at birth. The young prince was christened at Teodoli Palace, on 12 February 1776 by a Rev Salter. His godparents were the Duke and Duchess of Saxe-Gotha-Altenburg (his first cousin once-removed and his wife) and the Margrave of Brandenburg-Ansbach (his second cousin once-removed).