John Andrew Foster (5 May 1941 - 12 March 2009), known as John Foster, was a British philosopher and tutorial Fellow of Brasenose College, Oxford, from 1966 to 2005 (and then a Emeritus Fellow until his death in 2009). He authored several books, including The Case for Idealism (1982) and A World for Us: The Case for Phenomenalistic Idealism (2008). His A. J. Ayer (1985) was described by Anthony Quinton as "the only serious monograph" about Ayer's philosophy".