Mary Teston Luis Bell (3 December 1903 – 6 February 1979) was an Australian aviator and founding leader of the Women's Air Training Corps (WATC), a volunteer organisation that provided support to the Royal Australian Air Force (RAAF) during World War II. She later helped establish the Women's Auxiliary Australian Air Force (WAAAF), the country's first and largest women's wartime service, which grew to more than 18,000 members by 1944.