Frederick Ayer (December 8, 1822 - March 14, 1918) was an American businessman and the younger brother of patent medicine tycoon Dr. James Cook Ayer. In addition to his involvement in the patent medicine business, he is better known for his work in the textile industry. After buying the Tremont and Suffolk mills in Lowell, Massachusetts, he bought up many textile operations in nearby Lawrence, combining them in 1899 into the American Woolen Company, of which he was the first president. He was involved in other businesses of the time as well, such as being the co-founder of the Arctic Coal Company . He died on March 14, 1918, in Thomasville, Georgia, and is interred at Lowell Cemetery.