Ingrid Newkirk (born June 11, 1949) is an English-born animal rights activist, author, and president and co-founder of People for the Ethical Treatment of Animals (PETA), the world's largest animal rights organization. She is the author of several books about animal liberation, including Free the Animals (2000), with a foreword from Chrissie Hynde, and Making Kind Choices (2005), which has a foreword by Sir Paul McCartney.

Newkirk is best known for the issue awareness campaigns she organizes on behalf of PETA, in order to promote animal rights and veganism. In her will, for example, she has directed that her skin be turned into wallets, her feet into umbrella stands, and her flesh into "Newkirk Nuggets," then grilled on a barbecue. "We are complete press sluts," she told The New Yorker. "It is our obligation."

Under Newkirk’s leadership in the 1970s as the District of Columbia's first female poundmaster, legislation was passed to create the first spay/neuter clinic in Washington, D.C., as well as an adoption program, and the public funding of veterinary services, leading her to be named "Washingtonian of the Year" in 1980. At PETA, she has led successful campaigns to stop the use of animals in crash tests, has convinced companies from Gillette to Revlon to stop testing cosmetics on animals, and has persuaded grocery store chains such as Safeway to insist on higher welfare standards from the meat industry.