HRH Prince William Henry, Earl of Connaught, 1st Duke of Gloucester and Edinburgh (November 14, 1743 - August 25, 1805) was a British prince and military officer, younger brother of King George III.

He was born to Frederick Louis, Prince of Wales and Augusta of Saxe-Gotha at Leicester House in London. His brother King George III created him Duke of Edinburgh, Duke of Gloucester and Earl of Connaught in 1764.

Prince William Henry, Duke of Gloucester was most known for his secret marriage to Maria, Dowager Countess Waldegrave , an illegitimate granddaughter of Sir Robert Walpole. This marriage and that of his brother prompted the passing of the Royal Marriages Act. The Duke of Gloucester had three children by his wife -

• Her Highness Princess Sophia of Gloucester (1773-1844)

• Her Highness Princess Caroline of Gloucester (1774-1775)

• His Highness Prince William Frederick of Gloucester (1776-1834), m. HRH The Princess Mary, no issue

Prince William Henry was appointed (in an honorary fashion) to colonel of the 13th Regiment of Foot, 3rd Regiment of Foot Guards, and 1st Regiment of Foot Guards, and he became a field marshal on October 12, 1793. He died at Gloucester House in London.

Titles

• His Royal Highness Prince William Henry of Wales (1743-1764)
• His Royal Highness The Duke of Gloucester (1764-1805)