Lucy Wills, MA (Cantab), LRCP, MB BS (Lond) (10 May 1888 – 26 April 1964) was a leading English haematologist. She conducted seminal work in India in the late 1920s and early 1930s on macrocytic anaemia of pregnancy. Her observations led to her discovery of a nutritional factor in yeast which both prevents and cures this disorder.