投票悖论是一个由马奎斯·孔多塞在18世纪晚期提出的一个悖论。在这个假想情况中，集体倾向可以是循环性的，即使个人的倾向不是。

假设甲乙丙三人，面对ABC三个备选方案，有如以下的偏好排序：

无论投票结果是什幺，都会有至少两人认可的更优方案存在。

如果投票结果是A，则乙和丙都认为C比A更好。当结果是C时，甲和乙都认为B比C好。无论结果如何，多数人都会倾向于另一套方案。

The voting paradox (also known as Condorcet's paradox or the paradox of voting) is a situation noted by the Marquis de Condorcet in the late 18th century, in which collective preferences can be cyclic (i.e., not transitive), even if the preferences of individual voters are not cyclic. This is paradoxical, because it means that majority wishes can be in conflict with each other. When this occurs, it is because the conflicting majorities are each made up of different groups of individuals.