Dennis Jon McKenna (born December 17, 1950) is an American ethnopharmacologist and author. His research led to the development of natural products for Aveda Corporation as well as greater awareness of natural products and medicines. He has authored numerous scientific articles and books, including co-authoring the book Invisible Landscape with his brother Terence McKenna. McKenna now serves as a senior lecturer for the Center for Spirituality and Healing, part of the Academic Health Center at the University of Minnesota, Twin Cities.