美国例外论（英语：American Exceptionalism），又译美国卓异主义、美国例外主义、美式例外主义，一种理论与意识形态，认为美利坚合众国是个独特的国家，与其他国家完全不同。为亚历西斯·托克维里于1831年所杜撰之词句。有观点认为，美国例外论实质上已经成为美国凌驾于国际法之上，推行全球霸权主义和极端利己主义，干涉其他国家内政的借口和思想根源。

美国例外论的概念为，美利坚合众国与美国人在世界上地位独特，是世界上第一个，也是独一无二，以自由、个人主义、法律面前人人平等、自由放任资本主义等思想为建国基础的国家，人民特别富裕幸福，国家特别稳定强盛，并在世界上领导与保卫自由潮流，因此独特优越，具有其他国家无可比拟之处；因其为人类提供机会与希望，由注重于人身与经济自由的宪政理想所治理，衍生出独一无二的公私利益平衡。美利坚合众国有多项特征在政治学上独一无二，如反专制独裁的传统、个人主义、各社会主义政党不成气候、美洲大陆与世界其他地区在地理上的区隔、受到宗教——尤其是基督教大力影响。这些特征和开发程度相近的西欧与斯堪的那维亚半岛（北欧）国家、**、或影响拉丁美洲的马克思主义国家完全不同。

American exceptionalism is one of three related ideas. The first is that the history of the United States is inherently different from other nations. In this view, American exceptionalism stems from its emergence from the American Revolution, thereby becoming what political scientist Seymour Martin Lipset called "the first new nation" and developing a uniquely American ideology, "Americanism", based on liberty, egalitarianism, individualism, republicanism, democracy and laissez-faire for business. This ideology itself is often referred to as "American exceptionalism." Second is the idea that the US has a unique mission to transform the world. As Abraham Lincoln put it in the Gettysburg address (1863), Americans have a duty to see that "government of the people, by the people, for the people, shall not perish from the earth." Third is the sense that its history and its mission give the United States a superiority over other nations.