William Parr may refer to:
- William Parr, 1st Baron Parr of Kendal (1434-1483) - courtier and soldier, grandfather of Queen Katherine Parr
- William Parr, 1st Baron Parr of Horton (c. 1483 - 1546), son of the above
- William Parr, 1st Marquess of Northampton, brother of Queen Katherine Parr and leading courtier during the reigns of Edward VI and Elizabeth I