Sir John Key, 1st Baronet (16 August 1794 – 14 July 1858) was a wholesale stationer and Whig politician in England. He was elected Sheriff of the City of London in 1824 and Lord Mayor of London for two years, from 1830 to 1832. He was made a baronet in 1831, of Thornbury and Denmark Hill. In 1853 he ran for election to the office of Chamberlain of the City of London, emerging victorious after a closely fought contest with the young liveryman Benjamin Scott. He died in the office of Chamberlain, and Scott was elected unopposed in his stead.