David A. Evans (born January 11, 1941, Washington, D.C.) is the Abbott and James Lawrence Professor of Chemistry in the Department of Chemistry and Chemical Biology at Harvard University. He is a prominent figure in the field of organic chemistry and is best known for the development of aldol reaction methodology (the Evans' acyl oxazolidinone method).
Evans attended Oberlin College (A.B., 1963) and the California Institute of Technology (Ph.D., 1967).
Evans has made many scholarly contributions to the field of organic chemistry. Although he is best known for his work on the aldol reaction, he has also developed methodology for anionic oxy-Cope rearrangements, metal catalyzed hydroborations, and catalytic, enantioselective reactions based on bis-oxazoline (box) ligands. The Evans–Saksena reduction and Evans–Tishchenko reaction take their names from him.