Animal Liberation: A New Ethics for Our Treatment of Animals is a 1975 book by Australian philosopher Peter Singer. It is widely considered within the animal liberation movement to be the founding philosophical statement of its ideas. Singer himself rejected the use of the theoretical framework of rights when it comes to human and nonhuman animals. Following Jeremy Bentham, Singer argued that the interests of animals should be considered because of their ability to experience suffering and that the idea of rights was not necessary in order to consider them. He popularized the term "speciesism" in the book, which had been coined by Richard D. Ryder to describe the exploitative treatment of animals.

Peter Albert David Singer is an Australian moral philosopher who is Emeritus Ira W. DeCamp Professor of Bioethics at Princeton University. Singer's work specialises in applied ethics, approaching the subject from a secular, utilitarian perspective. He wrote the book Animal Liberation (1975), in which he argues for vegetarianism, and the essay "Famine, Affluence, and Morality", which argues the moral imperative of donating to help the poor around the world. For most of his career, he was a preference utilitarian. He revealed in The Point of View of the Universe (2014), coauthored with Katarzyna de Lazari-Radek, that he had become a hedonistic utilitarian.