Lloyd C. Gardner (born 1934) is an American historian, a member of the "Wisconsin School" of diplomatic history along with Walter LaFeber and Thomas J. McCormick. He was educated at the University of Wisconsin–Madison.
Gardner was the Charles and Mary Beard Professor of History at Rutgers University, where he taught since 1963. A specialist in 20th century History of U.S. foreign policy, Gardner has held several national fellowships, including two Fulbright Professorships in England and Finland, and a Guggenheim Fellowship. He is author or editor of 16 books on American foreign policy.
The Lloyd C. Gardner Fellowship Program in Leadership and Social Policy at Rutgers was established in his honor.