John Laurence Kulp (February 11, 1921 – September 25, 2006) was a 20th-century geochemist. He led major studies on the effects of nuclear fallout and acid rain. He was a prominent advocate in American Scientific Affiliation circles in favor of an Old Earth and against the pseudoscience of flood geology. Kulp died on September 25, 2006, at the age of 85.