Sir William Calthorpe KB (30 January 1410 – 15 November 1494) was an English knight and Lord of the Manors of Burnham Thorpe and Ludham in Norfolk.

Sir William Calthorpe was born on 30 January 1410 at Burnham Thorpe, in the English county of Norfolk.

He became the heir to his grandfather's lands in 1431, and his children inherited the manor at Ingham, in north-east Norfolk.

[2] He became locum tenens and Commissary-General to the late most noble and potent William, Duke of Norfolk, Earl of Pembroke, and Lord Great Chamberlain of England, Ireland and Aquitaine, during the minority of the Duke's son and heir, Henry, Earl of Exeter.

[2] Calthorpe was made a Knight of the Bath in the Tower of London, by King Edward IV, on the Coronation of his Queen, Elizabeth Woodville, Ascension Day.

[2] In June 1469, he was "sworn one of my lord of Gloucester's men", but the following year was recorded as being a supporter of the Readeption of Henry VI.

His second wife was Elizabeth (c. 1441-18 February 1505),[citation needed] eldest daughter and co-heir of Sir Miles Stapleton, of Ingham, Norfolk,[2] by his spouse, Katherine de la Pole (c. 1416-1488), who settled the manor of Hempstead, Norfolk, upon Elizabeth.