Thomas A. O'Halloran Jr. (13 April 1931 – 28 March 2015) was an American particle physicist.
After obtaining a Bachelor of Arts degree in physics at Oregon State University, O'Halloran served in the United States Navy for four years, on the USS Ruddy, and stateside in Las Vegas, before earning a doctorate in physics at University of California, Berkeley.
He completed his doctoral studies in 1963, advised by Gerson and Sulamith Goldhaber, then pursued postdoctoral research at Harvard University between 1964 and 1965.
[1] O'Halloran joined the University of Illinois Urbana-Champaign Department of Physics in 1966, as an assistant professor.
In 1989, O'Halloran was invited by a former student, Pierre Sokolsky, to serve as a visiting scholar at the University of Utah.