Ida, Lady Cockayne (1368 – 1 June 1426), born Ida or Edith de Grey, was a Cambro-Norman noblewoman, and the daughter of Reginald Grey, 2nd Baron Grey de Ruthyn, a powerful Welsh Marcher lord. The Greys of Ruthyn were the chief Marcher barons in the northern region of the Welsh Marches.Ida married Sir John Cockayne, Chief Baron of the Exchequer by whom she had six children.