Bonapartism is a political expression in the vocabulary of Marxism and Leninism, deriving from the career of Napoleon Bonaparte. Karl Marx was a student of Jacobinism and the French Revolution as well as a contemporary critic of the Second Republic and Second Empire. He used the term Bonapartism to refer to a situation in which what he saw as counter-revolutionary military officers seize power from revolutionaries, and then use selective reformism to co-opt the radicalism of the popular classes. In the process, Marx argued, Bonapartists preserve and mask the power of a narrower ruling class.

Marx saw both Bonaparte and his nephew Napoleon III as having corrupted revolutions in France in this way. Marx offered this definition of and analysis of Bonapartism in "The Eighteenth Brumaire of Louis Bonaparte," written in 1852. In this document, he drew attention to what he calls the phenomenon's repetitive history with one of his most quoted lines: "History repeats itself, first as tragedy, then as farce."

More generally "Bonapartism" is used to describe the replacement of civilian leadership by military leadership within revolutionary movements or governments. Many modern-day Trotskyists and other leftists use the phrase "left Bonapartist" to describe those like Stalin and Mao who controlled 20th century bureaucratic socialist regimes. The term could just as eaily apply to Leon Trotsky himself, since he was accused of using his position as commander of the Red Army to lever himself into power after the death of Lenin. Raymond Hinnebusch has characterized Hafez al-Asad's regime in Syria as Bonapartist.