Jacob "Jaap" Korevaar (born 25 January 1923, Lange Ruige Weide) is a Dutch mathematician. He was part of the faculty of the University of California San Diego and University of Wisconsin–Madison, as well as the University of Amsterdam (Korteweg-de Vries Institute for Mathematics). Korevaar became a member of the Royal Netherlands Academy of Arts and Sciences in 1975. He won the 1987 Lester R. Ford Award, and the 1989 Chauvenet Prize, for an essay on Louis de Branges de Bourcia's proof of the Bieberbach conjecture. In 2012 he became a fellow of the American Mathematical Society.