Sir Isaac Bayley Balfour (31 March 1853–30 November 1922)

British botanist. Appointed as Regius Professor of Botany at Glasgow University in 1879, he become Sherardian Professor of Botany at Oxford in 1884. In 1888 he became Professor of Botany at Edinburgh University and Regius Keeper of the Royal Botanic Garden there. FRS.