Onora Sylvia O'Neill, Baroness O'Neill of Bengarve CH CBE HonFRS FBA FMedSci MRIA (born 23 August 1941) is a British philosopher and a crossbench member of the House of Lords. The daughter of Sir Con O'Neill, she was educated partly in Germany and at St Paul's Girls' School, London, before studying philosophy, psychology and physiology at Somerville College, Oxford. She went on to complete a doctorate at Harvard University, with John Rawls as supervisor. During the 1970s she taught at Barnard College, the women's college in Columbia University, New York City. In 1977 she returned to Britain and took up a post at the University of Essex; she was Professor of Philosophy there when she became Principal of Newnham College, Cambridge in 1992.