James Edward McDonald (May 7, 1920 – June 13, 1971) was an American physicist.
He is best known for his research regarding UFOs.
McDonald was senior physicist at the Institute for Atmospheric Physics and professor in the Department of Meteorology, University of Arizona, Tucson.
McDonald campaigned in support of expanding UFO studies during the mid and late 1960s, arguing that UFOs represented an important unsolved mystery which had not been adequately studied by science.
He was one of the more prominent figures of his time who argued in favor of the extraterrestrial hypothesis as a plausible, but not completely proved, model of UFO phenomena.
McDonald interviewed over 500 UFO witnesses, uncovered many important government UFO documents, and gave presentations of UFO evidence.
He testified before Congress during the UFO hearings of 1968.
McDonald also gave a famous talk called "Science in Default" to the American Association for the Advancement of Science (AAAS).
It was a summary of the current UFO evidence and a critique of the 1969 Condon Report UFO study.