He is left-handed.
He likes R&B music.
He supports Aston Villa.
He has a black Labrador, called Widgeon, and shares the Royal Family's love of horses.
He lives at Highgrove in Doughton, Gloucestershire and often spends time at nearby Duchy Home Farm.
His brother Harry is two years younger than him.
His dad is Prince Charles.
His mum, Princess Diana, died in a car crash in Paris in 1997.
Charles and Diana married in 1981 and divorced in 1996.
William's grandmother is the Queen, Elizabeth II.