Eric Foner (/ˈfoʊnər/; born February 7, 1943) is an American historian. He writes extensively on American political history, the history of freedom, the early history of the Republican Party, African American biography, the American Civil War, Reconstruction, and historiography, and has been a member of the faculty at the Columbia University Department of History since 1982. He is the author of several popular textbooks, such as the Give Me Liberty series for high school classrooms. According to the Open Syllabus Project, Foner is the most frequently cited author on college syllabi for history courses.

Foner has published several books on the Reconstruction period, starting with Reconstruction: America's Unfinished Revolution, 1863–1877 in 1988. His online courses on "The Civil War and Reconstruction", published in 2014, are available from Columbia University on ColumbiaX.

In 2011, Foner's The Fiery Trial: Abraham Lincoln and American Slavery (2010) won the Pulitzer Prize for History, the Lincoln Prize, and the Bancroft Prize. Foner previously won the Bancroft Prize in 1989 for his book Reconstruction: America's Unfinished Revolution, 1863–1877. In 2000, he was elected president of the American Historical Association. He was elected to the American Philosophical Society in 2018.

Foner was born February 7, 1943, in New York City, New York, the son of Jewish parents, Liza (née Kraitz), a high school art teacher, and historian Jack D. Foner, who was active in the trade union movement and the campaign for civil rights for African Americans. Eric Foner describes his father as his "first great teacher", and recalls how

deprived of his livelihood while I was growing up, he supported our family as a freelance lecturer. ... Listening to his lectures, I came to appreciate how present concerns can be illuminated by the study of the past—how the repression of the McCarthy era recalled the days of the Alien and Sedition Acts, the civil rights movement needed to be viewed in light of the great struggles of black and white abolitionists, and in the brutal suppression of the Philippine insurrection at the turn of the century could be found the antecedents of American intervention in Vietnam. I also imbibed a way of thinking about the past in which visionaries and underdogs—Tom Paine, Wendell Phillips, Eugene V. Debs, and W. E. B. Du Bois—were as central to the historical drama as presidents and captains of industry, and how a commitment to social justice could infuse one's attitudes towards the past.

After graduating from Long Beach High School in 1959, Foner enrolled at Columbia University, where he was originally a physics major, before switching to history after taking a year-long seminar with James P. Shenton on the Civil War and Reconstruction during his junior year. "It probably determined that most of my career has been focused on that period," he recalled years later. A year later, in 1963, Foner graduated summa cum laude with a BA in history. He studied at the University of Oxford as a Kellett Fellow; he received a BA from Oriel College in 1965, where he was a member of the college's 1966 University Challenge winning team, though he did not appear in the final, having already returned to the US. After graduating from Oxford, Foner returned to Columbia where he earned his doctoral degree in 1969 under the supervision of Richard Hofstadter. His doctoral thesis, published in 1970 as Free Soil, Free Labor, Free Men: The Ideology of the Republican Party Before the Civil War, explored the deeply rooted ideals and interests that drove the northern majority to oppose slavery and ultimately wage war against Southern secession.

Foner is a leading authority on the Reconstruction Era. In a seminal essay in American Heritage in October 1982, later reprinted in Reviews in American History, Foner wrote,

In the past twenty years, no period of American history has been the subject of a more thoroughgoing reevaluation than Reconstruction—the violent, dramatic, and still controversial era following the Civil War. Race relations, politics, social life, and economic change during Reconstruction have all been reinterpreted in the light of changed attitudes toward the place of blacks within American society. If historians have not yet forged a fully satisfying portrait of Reconstruction as a whole, the traditional interpretation that dominated historical writing for much of this century has irrevocably been laid to rest.