Sheila Marie Evans Widnall (born July 13, 1938) is an American aerospace researcher and Institute Professor at the Massachusetts Institute of Technology.
She served as United States Secretary of the Air Force between 1993 and 1997, making her the first female Secretary of the Air Force and the first woman to lead an entire branch of the US military in the Department of Defense.
She was inducted into the National Women's Hall of Fame in 2003.