Jan de Boer (born 29 June 1967, Doniawerstal) is a Dutch theoretical physicist specializing in string theory. After a double masters degree in mathematics and physics at the University of Groningen, De Boer obtained his PhD from Utrecht University with the dissertation Extended conformal symmetry in non-critical string theory. Since 2000 he has been professor of theoretical physics at the University of Amsterdam. From 1946 to 1981 an unrelated Jan de Boer (1911–2010) was professor of theoretical physics at the same department of the University of Amsterdam. His specialty was thermodynamics.