J. Baird Callicott (born 1941) is an American philosopher whose work has been at the forefront of the new field of environmental philosophy and ethics. He is a University Distinguished Research Professor and a member of the Department of Philosophy and Religion Studies and the Institute of Applied Sciences at the University of North Texas. Callicott held the position of Professor of Philosophy and Natural Resources at the University of Wisconsin–Stevens Point from 1969 to 1995, where he taught the world's first course in environmental ethics in 1971. From 1994 to 2000, he served as vice president then president of the International Society for Environmental Ethics. Other distinguished positions include visiting professor of philosophy at Yale University; the University of California, Santa Barbara; the University of Hawaiʻi; and the University of Florida.

Aldo Leopold's A Sand County Almanac is one of environmental philosophy's seminal texts, and Callicott is widely considered to be the leading contemporary exponent of Leopold's land ethic. Callicott's book In Defense of the Land Ethic (1989) explores the intellectual foundations of Leopold's outlook and seeks to provide it with a more complete philosophical treatment; and a following publication titled Beyond the Land Ethic (1999) further extends Leopold's environmental philosophy. Callicott's Earth’s Insights (1994) is also considered an important contribution to the budding field of comparative environmental philosophy; a special edition of the journal Worldviews: Environment, Culture, Religion (Volume 1, Number 2) was devoted to scholarly reviews of the work. Callicott is co-Editor-in-Chief with Robert Frodeman of the award-winning, two-volume A-Z Encyclopedia of Environmental Ethics and Philosophy, published by Macmillan in 2009. He is also author of numerous journal articles and book chapters in environmental philosophy and has served as editor or co-editor of many books, textbooks, and reference works in the same field.