Lee Muller Thomas (born June 13, 1944) was Administrator of the United States Environmental Protection Agency from 1985 to 1989 under President Ronald Reagan. He succeeded William Ruckelshaus. He is a Republican. Thomas led the EPA when the report Unfinished Business: A Comparative Assessment of Environmental Problems was released. Thomas earned his Masters in Education from the University of South Carolina, where he did postgraduate work in psychology. He received his Bachelor of Arts degree in psychology from the University of the South in Sewanee, Tennessee.