John Dewar may refer to:
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Dewar's Scotch Whisky, made by
John Dewar & Sons
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John Dewar (academic) (born 1959), Vice-Chancellor of La Trobe University
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John Dewar Sr. (1805–1880), founder of ''John Dewar & Sons''
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John Dewar, 1st Baron Forteviot (1856–1929), son of John Dewar, Sr.
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John Dewar, 2nd Baron Forteviot (1885–1947), Scottish businessman and soldier
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John Dewar (RAF officer) (1907–1940), World War II Royal Air Force fighter pilot
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John A. Dewar (1863–1945), farmer and political figure on Prince Edward Island
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John Michael Dewar (1883–1941), British gynaecologist and ornithologist
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John Dewar (MP) (1740s–1795), British politician
{{disambiguation, hn=Dewar, John