Kenneth Stephen Brown (born 1945) is a professor of mathematics at Cornell University, working in category theory and cohomology theory. Among other things, he is known for Ken Brown's lemma in the theory of model categories. He is also the author of the book Cohomology of Groups (Graduate Texts in Mathematics 87, Springer, 1982).
Brown earned his Ph.D. in 1971 from the Massachusetts Institute of Technology, under the supervision of Daniel Quillen (Abstract Homotopy Theory and Generalized Sheaf Cohomology). He was an invited speaker at the International Congress of Mathematicians in 1978 in Helsinki. In 2012 he became a fellow of the American Mathematical Society.