The Anthropological Society of London was founded in 1863 by Richard Francis Burton and Dr. James Hunt. It broke away from the existing Ethnological Society of London, founded in 1842, and defined itself in opposition to the older society. The Anthropological Society, Hunt proclaimed, would concern itself with the collection of facts and the identification of natural laws that explained the diversity of humankind. It would also cast its intellectual nets more broadly, dealing with the physical as well as the cultural aspects of humans.

The real differences between the two societies ran much deeper. The members of the Ethnological Society were, on the whole, inclined to believe that humans were shaped by their environment; when Charles Darwin published his theory of evolution by natural selection, they supported it. They also believed in monogenism and tended to be politically liberal, especially on matters related to race. Hunt and his closest followers were, in contrast, vehemently anti-Darwinian and strong supporters of polygensim. They found the Ethnological Society's politics distasteful, and (for example) supported the Confederacy in the American Civil War. The issue that most sharply divided the two groups was the "Negro question." Hunt believed that Africans belonged to a different species than Caucasians, that they were substantially and irredeemably inferior, and that slavery was the role for which they were best suited. Many leading members of the Ethnological Society were, in contrast, fiercely committed to Britain's attempts to stamp out the slave trade.

The two societies coexisted warily for eight years, but merged in 1871 to form the Royal Anthropological Institute of Great Britain.