Mabel Josephine (Jo) Mackerras (née Bancroft) (7 August 1896 – 8 October 1971) was an Australian zoologist, entomologist and parasitologist.

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".

[3] On 8 October 1971, Mackerras of Ridley Street, Turner and member of Council for Scientific and Industrial Research, Division of Entomology died in Canberra.

She then opened a small private practice and still found time for a part-time appointment at the Rachel Forster Hospital for Women and Children.

In 1930, Mackerras joined the unit led by her husband, as assistant entomologist at the Council for Scientific and Industrial Research's division of economic entomology in Canberra .

Her research on blowfly infestation and ephemeral fever led to several individual and joint publications with husband Ian Mackerras and Frank Macfarlane Burnet.

[12][13] After WWII broke out, on 7 February 1942, Mackerras joined the Australian Army Medical Corps as captain and was stationed in the Sydney area.

To seek a solution to this burgeoning problem affecting the troops, Mackerras, Hugh Ward and Bill Keogh proposed an organization that would focus on the scientific investigation of the disease.

Her work proved beneficial to reduce the incidence of infection in the armed forces, and delivered a scientific basis for studying the effects of pharmaceutical drugs on the malarial parasite.

At the Yeerongpilly laboratories, Ian initiated studies on the control of the cattle tick and Jo commenced work on the Simuliidae (blackflies).

[23][24] The Mackerras couple collaborated on definitive works on the haematozoan parasites of Australian birds, frogs and fishes and produced several papers in this area.