Oxford married firstly, Margaret Neville, the daughter of Richard Neville, 5th Earl of Salisbury, by Alice, the daughter of Thomas Montagu, 4th Earl of Salisbury. Oxford's first wife was the sister of Richard Neville, 16th Earl of Warwick, the Kingmaker, making Oxford the uncle of Isabel Neville, Duchess of Clarence as the wife of George Plantagenet, and Anne Neville, the Duchess of Gloucester and later Queen of England after her husband, Richard, was crowned Richard III. Margaret Neville died between 20 November 1506 and 14 January 1507.