Professor Helena Sheehan is an academic philosopher, historian of science, and writer on communication studies, politics, and philosophical (particularly Marxist) subjects. Sheehan is a retired (Professor Emeritus) Communications lecturer at Dublin City University and has been a visiting professor at the University of Cape Town.

Born in the United States, Sheehan describes her childhood as Catholic and conservative, Sheehan began studies her university and taught primary school as a nun. As a result of studying, she became an agnostic and liberal, then later an atheist and radical. She then left the convent. Sheehan earned a Bachelor of Science degree in 1967 from St. Joseph's University (then known as St. Joseph's College) in Philadelphia, followed by an MA in 1970 from Temple University in Philadelphia. She earned a PhD in 1980 from Trinity College (Dublin) in philosophy – then already active in the Trinity College Dublin Communist Society.

As an historian of science, Sheehan develops the view that Marx and Engels shared fundamentally the same view on the philosophy of science. A Marxist humanist, Sheehan has written critically of Lysenkoism and Stalin's impact on scientific development.

Sheehan has lectured at the Humanist Association of Ireland.

In her personal life, Sheehan is the partner of the trade unionist Sam Nolan.