Steven Weinberg (; born May 3, 1933) is an American theoretical physicist and Nobel laureate in Physics for his contributions with Abdus Salam and Sheldon Glashow to the unification of the weak force and electromagnetic interaction between elementary particles.
He holds the Josey Regental Chair in Science at the University of Texas at Austin, where he is a member of the Physics and Astronomy Departments. His research on elementary particles and physical cosmology has been honored with numerous prizes and awards, including in 1979 the Nobel Prize in Physics and 1991 the National Medal of Science. In 2004 he received the Benjamin Franklin Medal of the American Philosophical Society, with a citation that said he is "considered by many to be the preeminent theoretical physicist alive in the world today." He has been elected to the US National Academy of Sciences and Britain's Royal Society, as well as to the American Philosophical Society and the American Academy of Arts and Sciences.
Weinberg's articles on various subjects occasionally appear in The New York Review of Books and other periodicals. He has served as a consultant at the U. S. Arms Control and Disarmament Agency, President of the Philosophical Society of Texas, and member of the Board of Editors of Daedalus magazine, the Council of Scholars of the Library of Congress, the JASON group of defense consultants, and many other boards and committees.