Henry Sidgwick (May 1838 – 28 August 1900) was an English utilitarian philosopher and economist.

He was one of the founders and first president of the Society for Psychical Research and a member of the Metaphysical Society.

He also founded Newnham College in 1875, a women-only constituent college of the University of Cambridge.

Brought up in the Church of England, he drifted away from orthodox Christianity, and as early as 1862 he described himself as a theist, independent from established religion. For the rest of his life, although he regarded Christianity as "indispensable and irreplaceable – looking at it from a sociological point of view," he found himself unable to return to it as a religion.

"Losing My Religion":Sidgwick, Theism, and the Struggle for Utilitarian Ethics in Economic Analysis by Steven G. Medema.