Lord John Grey (1523/24 – 19 November, 1564) was an English nobleman and Tudor courtier, who was seated at Pirgo Place after 1559.
Lord John was at one stage sentenced to death for his involvement in Wyatt's Rebellion against Mary I, but was later released from attainder. Grey was restored to his original position by Queen Mary's successor, Elizabeth I; Queen Elizabeth also granted him Pirgo Place in Essex as well as making him Guardian of Lady Catherine Grey, his niece, and sister of the late Lady Jane Grey, in 1563. However, Lord John was again imprisoned shortly before his death, after publishing a book asserting Catherine [Grey] to be the legitimate heir to the English throne.
Lord John Grey was the youngest surviving son of Thomas Grey, 2nd Marquess of Dorset and Margaret, widow of William Medley, and daughter of Sir Robert Wotton, of Boughton Malherbe, Kent.
His elder brothers, Henry, 3rd Marquess of Dorset (created Duke of Suffolk in 1551) and Lord Thomas Grey, were executed for treason on Tower Hill in 1554.
Grey married Mary Browne, daughter of Sir Anthony Browne KG by his first wife, Alice née Gage.