John de Vere, 13th Earl of Oxford, the second son of John de Vere, 12th Earl of Oxford, and Elizabeth Howard, a first cousin of John Howard, 1st Duke of Norfolk, was one of the principal Lancastrian commanders during the English Wars of the Roses.

John de Vere, 12th Earl of Oxford, was the son of Richard de Vere, 11th Earl of Oxford, and his second wife, Alice Sergeaux (1386–1452). A Lancastrian loyalist during the latter part of his life, he was convicted of high treason and executed on Tower Hill on 26 February 1462.