Sadleir may refer to: People with the surname Franc Sadleir (1775–1851), Irish academic James Sadleir (c.1815 – 1881), Irish financier and politician John Sadleir (1813–1856), Irish financier and politician Lynette Sadleir (b. 1963), Canadian-born swimmer Michael Sadleir (1888–1957), British author and bibliophile Ralph Sadleir (1579–1661), English landowner Thomas Sadleir (died 1607) (c.1536–1607), English landowner and politician Thomas Sadleir (1882–1957), Irish genealogist and herald Lionel Sadleir-Jackson (1876–1932), British army officer Places Sadleir, New South Wales See also Sadleirian Professor of Pure Mathematics, University of Cambridge Saddler (disambiguation) Sadler (disambiguation) Sadlier, a surname