George Henry Lewes (; 18 April 1817 – 30 November 1878) was an English philosopher and critic of literature and theatre. He was also an amateur physiologist. American feminist Margaret Fuller is known to have called Lewes a "witty, French, flippant sort of man". He became part of the mid-Victorian ferment of ideas which encouraged discussion of Darwinism, positivism, and religious skepticism. However, he is perhaps best known today for having openly lived with Mary Ann Evans, who wrote under the pen nameGeorge Eliot, as soulmates whose lives and writings were enriched by their relationship, though they never married each other.