James Dewar (1842–1923) was a Scottish chemist and physicist.
James Dewar may also refer to: James Dewar (musician) (1942–2002), Scottish bassist and vocalist James Dewar (baker) (1897–1985), Canadian inventor of the Twinkie snack cake James Dewar (judge) (1797–1830), British jurist and the Chief Justice of the Supreme Court of Bombay James Dewar (cricketer), English cricketer and British Army officer James Dewar (footballer), of Everton F.C. season 1892–93
See also James Dewar Bourdillon, British civil servant Jim Dewar (disambiguation)