Reform or Revolution, also titled Social Reform or Revolution? is an 1899 pamphlet by Polish-German Marxist theorist Rosa Luxemburg.

Luxemburg argues that trade unions, reformist political parties and the expansion of social democracy—while important to the proletariat's development of class consciousness—cannot create a socialist society as Eduard Bernstein, among others, argued. Instead, she argues from a historical materialist perspective that capitalism is economically unsustainable and will eventually collapse and that a revolution is necessary to transform capitalism into socialism. The pamphlet was heavily influential in revolutionary socialist circles and along with Luxemburg's other work an important precursor to left communist theory.

The writing and publication of Social Reform or Revolution took place against the backdrop of party congresses in 1899, 1901 and 1903. Luxemburg's positions won out against Bernstein, with the SPD remaining committed to orthodox Marxism.