Anthony Clifford "A. C." Grayling is a British philosopher. In 2011 he founded and became the first Master of New College of the Humanities, an independent undergraduate college in London. Until June 2011, he was Professor of Philosophy at Birkbeck, University of London, where he taught from 1991. He is also a supernumerary fellow of St Anne's College, Oxford.

He is a director and contributor at Prospect Magazine, as well as a Vice President of the British Humanist Association. His main academic interests lie in epistemology, metaphysics and philosophical logic. He has described himself as "a man of the left" and is associated in Britain with the new atheism movement, and is sometimes described as the 'Fifth Horseman of New Atheism'. He appears in the British media discussing philosophy.