William de Vere was a medieval Bishop of Hereford.
The fourth son of Aubrey de Vere II and Adeliza of Clare and brother of Aubrey de Vere III first earl of Oxford, he spent part of his youth at the court of King Henry I of England and his Queen consort Adeliza of Leuven.
He was promised the chancellorship of England by the Empress Matilda in the 1141 charter by which his brother was made earl, but that was a contingent promise that was not fulfilled. He later entered the household of Archbishop Theobald of Canterbury (d. 1163), a near-contemporary of Thomas Becket and John of Salisbury, who also served the archbishop in the 1150s. He was briefly a secular canon of St. Paul's, London, about 1163, but apparently resigned to become an Augustinian or regular canon at St. Osyth's Priory at Chich, Essex. From there he was recruited by King Henry II to supervise the rebuilding at Waltham Abbey in Essex, which the king had undertaken in the 1170s. His name is one of two listed in the Pipe Rolls as receiving monies toward that project.
King Henry employed William de Vere as an itinerant justice, then nominated him as Bishop of Hereford on May 25 1186. He was consecrated on August 10 1186. In that office he occasionally continued to serve as a royal justice. He is credited with having extended the east end of Hereford Cathedral, constructing the transitional retrochoir, two transept chapels, and possibly a lady chapel (the latter two areas replaced by his successors). He is also thought to have constructed the bishop's palace at Hereford. He expanded the work of his predecessors in the administration of the diocese and raised the educational level of the secular canons of the cathedral, employing Gerald of Wales and Robert Grosseteste.
As a canon at St. Osyth's, William wrote a Latin life of that saint which now exists only in fragments recorded by John Leland in the sixteenth century. In that work he also praised his parents and sister. He is thought to have visited the Holy Lands. He was a friend of Bishop Arnulf of Liseux, and may have studied in Paris. He donated a relic of St. Osyth to Waltham Abbey, and promoted the cult of that saint at Hereford Cathedral.
He was one of several bishops who excommunicated Prince John and his supporters in 1194, and was present at Winchester Cathedral for the recoronation of King Richard I in April 1194. He died 24 December 1198 and is buried in Hereford Cathedral, where his tomb with effigy can be found.