Charles Lathrop Parsons (March 23, 1867, New Marlboro, Massachusetts-February 13, 1954 Pocasset, Massachusetts) was an American chemist. He was a professor at the University of New Hampshire for twenty years, and then a chemist and mineralogist at the U.S. Bureau of Mines. For nearly forty years, Parsons served as executive secretary of the American Chemical Society, becoming known as "Mr. ACS" and substantially influencing the formation of the association.