Ellen Dymphna Cusack AM (21 September 1902 – 19 October 1981) was an Australian writer and playwright.

[1] Born in Wyalong, New South Wales, Cusack was educated at Saint Ursula's College, Armidale, New South Wales[2] and graduated from the University of Sydney with an honours degree in arts and a diploma in Education.

Her collaborative novels were Pioneers on Parade (1939) with Miles Franklin, and Come In Spinner (1951) with Florence James.

She contributed to the world peace movement during the Cold War era as an antinuclear activist.

[9] In 2011, Cusack was one of 11 authors, including Elizabeth Jolley and Manning Clark, to be permanently recognised by the addition of brass plaques at the Writers' Walk, Sydney.