Mary Engle Pennington (1872-1952) was an American bacteriological chemist and refrigeration engineer. Pennington's involvement with refrigerated boxcar design at the Food Research Laboratory led to an interest in the entire process of transporting and storing perishable food, including both refrigerated transport and home refrigeration. In 1919, Pennington accepted a position with a private firm, American Balsa, which manufactured insulation for refrigeration units. She left the firm in 1922 to start her own consulting business, which she ran until her retirement in 1952. Mary Engle Pennington was the recipient of the Garvan-Olin Medal, the highest award given to women in the American Chemical Society. She is also an inductee of both the National Women's Hall of Fame and the ASHRAE Hall of Fame.