Gilbert Crispin (c. 1055 – 1117) was a Christian author and Anglo-Norman monk, appointed by Archbishop Lanfranc in 1085 to be the abbot, proctor and servant of Westminster Abbey, England. Gilbert became the third Norman Abbot of Westminster to be appointed after the Norman Conquest, succeeding Abbot Vitalis of Bernay.
He was probably the grandson of Gislebert Crispin, Baron of Bec, although the Crispin line—being a root of many noble English families—is notoriously convoluted and sometimes vague. His father may have been William Crispin, who fought at Senlac (the Norman name for the Battle of Hastings), and his mother Eve the daughter of Simon de Montfort l'Aumary. One source claims Gilbert was present, with his brother Milo, as camp boys at the Battle of Hastings – possibly even watching as his father and another relation, Gilbert of Tillières, charged the Anglo-Saxons with Henry de Ferrers, the latter two each having brought a large company into the field. He was closely related to Robert Crispin (Latin Ro(d)bertus Crispinus) a Norman mercenary who died in 1073.
Gilbert had known Saint Anselm, since Gilbert was a young monk under Anselm at the Abbey of Bec, Normandy. There Gilbert was said to have: "become a perfect scholar in all the liberal arts". In 1093, Saint Anselm became Archbishop of Canterbury. Gilbert promoted Anselm's arguments in his disputes with King Henry I of England. Gilbert was probably useful to Anselm's cause, since as well as being an Abbot, he apparently also acted as a general administrator to the King.