Tom Regan was an American philosopher who specialized in animal rights theory. He was professor emeritus of philosophy at North Carolina State University, where he taught from 1967 until his retirement in 2001.
Regan was the author of numerous books on the philosophy of animal rights, including The Case for Animal Rights (1983), one of a handful of studies that have significantly influenced the modern animal rights movement. In these, he argued that non-human animals are what he calls the "subjects-of-a-life", just as humans are, and that, if we want to ascribe value to all human beings regardless of their ability to be rational agents, then to be consistent, we must similarly ascribe it to non-humans.