John Bourchier, born about 1467, was the only son of Sir Humphrey Bourchier (d.1471) and Elizabeth Tilney (d.1497), the daughter and sole heir of Sir Frederick Tilney of Boston, Lincolnshire.
By his mother's first marriage, Bourchier had two sisters, Anne, who married Thomas Fiennes, 8th Baron Dacre of Gilsland, and Margaret, who married firstly, John Sandys, secondly, Sir Thomas Bryan, and thirdly, David Zouche.