Richard D. Ryder (born 1940) is a British psychologist who, after performing psychology experiments on animals began to speak out against the practice and became and one of the pioneers of the modern animal liberation and animal rights movements.

A former chairman of the Royal Society for the Prevention of Cruelty to Animals, and a past president of Britain's Liberal Democrat Animal Protection Group, Ryder is currently (April, 2004) parliamentary consultant to the Political Animal Lobby .

Ryder coined the term speciesism, using it first in a privately-printed leaflet published in Oxford in 1970.