社会契约（Social Contract）是一种概念，用以解释个人和政府之间的适当关系。社会契约主张：个人融入政治社会是透过一个相互同意的过程，当中，个人同意遵守共同的规则，并接受相应的义务，以保护自己和其他人不受暴力和其他种类的伤害。社会契约理论对催生主权在民这一政治理念发挥了重要的历史作用。大多数社会契约理论的出发点，是对不存在任何政治秩序的人类生存条件作启发式的审视，通常称为「自然状态」。在这种情况下，个人的行动只受他们个人的权力和良心所约束。从这个共同的起点，社会契约论者各以不同的方式证明，为什么一个理性的个人自愿放弃他自然的自由，获得政治秩序的好处。

In moral and political philosophy, the social contract or political contract is a theory or model, originating during the Age of Enlightenment, that typically addresses the questions of the origin of society and the legitimacy of the authority of the state over the individual. Social contract arguments typically posit that individuals have consented, either explicitly or tacitly, to surrender some of their freedoms and submit to the authority of the ruler or magistrate (or to the decision of a majority), in exchange for protection of their remaining rights. The question of the relation between natural and legal rights, therefore, is often an aspect of social contract theory. The Social Contract (Du contrat social ou Principes du droit politique) is also the short title of a 1762 book by Jean-Jacques Rousseau on this topic.