Dwaine O. Cowan (25 November 1935 – 5 May 2006) was an American chemist. He was a professor of chemistry at The Johns Hopkins University. He is best known for his pioneering work in the field of organic conductors. His other research interests included organometallic chemistry, organic photochemistry, organic chemistry, metallocenes and the synthesis of heterocyclic compounds containing sulfur, selenium, and tellurium.