Gail Lewis is a British writer, psychotherapist, researcher, and activist. She is visiting senior fellow in the Department of Gender Studies at the London School of Economics, and Reader Emerita of Psychosocial Studies at Birkbeck College, London. She trained as a psychodynamic psychotherapist at the Tavistock Clinic.

Lewis was born and raised in London; her mother was white and her father was from British Guiana. Her 2009 article "Birthing Racial Difference: conversations with my mother and others" uses autobiographical references and reflections on psychoanalysis and sociology to "explore how 'race' has operated as structuring principle in Britain since the end of the Second World War", and "mixed-race, mother-child relations".

Lewis studied Social Anthropology at the London School of Economics (LSE), followed by an MPhil in Development Studies at the University of Sussex. She passed her PhD in Social Policy with the Open University, and taught in the Open University Social Sciences Faculty between 1995 and 2004 and 2007 to 2013.

Lewis was Reader in Psychosocial Studies in the Department of Psychosocial Studies at Birkbeck College until 2019, having joined the department in 2013 and served as Assistant Dean between 2015 and 2017. She was Head of Department of the Institute of Women's Studies at Lancaster University.