Sir Henry Sidney (1529 – 5 May 1586), lord deputy of Ireland, is the eldest son of Sir William Sidney of Penshurst, a prominent politician and courtier during the reigns of Henry VIII and Edward VI, from both of whom he receives extensive grants of land, including the manor of Penshurst in Kent, which become the principal residence of the family.

Henry Sidney is brought up at court as the companion of Prince Edward, afterwards King Edward VI, and he continues to enjoy the favor of the Crown, particularly throughout the reign of Queen Elizabeth I.