Catherine of Lancaster (Castilian: Catalina; 31 March 1373 – 2 Jun 1418) was Queen of Castile as the wife of King Henry III of Castile.

Queen Catherine is the daughter of John of Gaunt, 1st Duke of Lancaster, and his second wife, Constance of Castile (the daughter and heir of King Peter of Castile, who dies at the hands of his half brother Henry II).

She is born in Hertford Castle, her father's chief country home, on 31 March 1373.

Catherine becomes Queen of Castile through her marriage to Henry III.