Elisabeth “Lisa” Anne Lloyd is an American philosopher of science specializing in the philosophy of biology. She is currently Distinguished Professor of History and Philosophy of Science and Medicine and Adjunct Professor of biology at Indiana University, Bloomington, affiliated faculty scholar at the Kinsey Institute for Research in Sex, Gender, and Reproduction and Adjunct Faculty at the Center for the Integrative Study of Animal Behavior.

Lloyd earned her BA in science and political theory from University of Colorado, Boulder and studied under Bas van Fraassen at Princeton University for a PhD in philosophy. While at Princeton, she spent a year studying with Richard C. Lewontin at Harvard’s Museum of Comparative Zoology.

She worked as an assistant professor in the Department of Philosophy at University of California, San Diego and then was assistant professor, then associate professor, then full professor in the Department of Philosophy at the University of California, Berkeley before moving to Indiana University.

Her 2005 book, The Case of the Female Orgasm, was widely discussed in the scholarly and popular press. The book criticizes what it portrays as anti-scientific biases infecting the many proposed adaptive explanations of female orgasm. Lloyd goes on to argue that the available evidence, such as from sexology studies, is far more supportive of a neutral “byproduct” explanation put forward by Donald Symons, under which female orgasm is the result of orgasm developing as a species trait due to its critical role in males for procreation (akin to explanations for why nipples, which are required for nursing in females, are also present in males).

In 2022, she was elected a Fellow of the American Academy of Arts & Sciences.