Mabel Josephine (Jo) Mackerras (née Bancroft) (7 August 1896 – 8 October 1971) was an Australian zoologist, entomologist and parasitologist. Her research and life's work contributed to entomology, veterinary medicine and medical science. Throughout her life she held a wide range of positions and duties that included Army medical officer, entomologist, medical scientist, and parasitologist. Mackerras was a major during WWII and served in the Army Malaria Research Unit. In an application for King's Birthday Honours her work earned the citation,: "few women can have made a greater contribution to the Allied war effort".