Allen Carl Guelzo (born 1953) is an American historian who serves as the Thomas W. Smith Distinguished Research Scholar and director of the Initiative on Politics and Statesmanship in the James Madison Program at Princeton University.

[10] His interest in the American Civil War was partially motivated by his grandmother, who had attended lectures by the Grand Army of the Republic as a child.

[11][12] To that effect, he cites the ex-slaves who testified that Lincoln, specifically his Emancipation Proclamation, was responsible for freeing them.

"[14] Rachel Shelden has noted that Guelzo's Fateful Lightning: A New History of the Civil War and Reconstruction (2012) is heavily focused on Lincoln.

She says he underplays the recent scholarship on the home front, environmental concerns, and medical issues and gives only cursory attention to the black experience or to the complexities of Reconstruction.

[15] In 2019, Guelzo denounced The 1619 Project as "polemic," "conspiracy theory," "ignorance," and "evangelism for a gospel of disenchantment whose ultimate purpose is the hollowing out of the meaning of freedom.

[17] He responded by writing that "I will take the opportunity of any platform offered me short of outright tyrants, depraved fools and genocidal murderers to talk about American history.

[20] Guelzo received the 2013 Guggenheim-Lehrman Prize in Military History for Gettysburg: The Last Invasion at an awards ceremony in New York on March 17, 2014.

[23] Guelzo was a recipient of the 2018 Bradley Prize for his "contributions [which] have shaped important debate, thought and research on one of the most critical periods of American history.

In 1980, Guelzo was ordained as a presbyter in the Reformed Episcopal Church, about which he wrote a history early in his career.