法治（英语：nomocracy，rule of law），又称为依法而治、以法治国或法之支配，法学及政治学名词，将国家，政府与政治领袖都置于法律的规范之下，将这个原则作为政治体制的基础，称为法治。在这种社会中，法律是社会最高的规则，具有凌驾一切的地位。所谓“凌驾一切”，指的是任何人包括管治机构、法律制订者和运行者都必需遵守，没有任何人或机构可以凌驾法律。这些法律本身是经过特定的立法进程产生的，以确保法律符合人民的集体意愿。

法治与另一个的名词，法管（rule by law），在意义上有些许不同。一个法治的社会中，由人民的意志来制定法律，政府（特别是行政机关）的行为受限于法律，必须是法律许可的，不能够违反法律的规则。但是在法管之下，政府透过法律来控制人民，人民必须受到法律拘束，但是政府与执政者本身超越法律，不必受到法律限制。

The rule of law is the legal principle that law should govern a nation, as opposed to being governed by arbitrary decisions of individual government officials. It primarily refers to the influence and authority of law within society, particularly as a constraint upon behaviour, including behaviour of government officials. The phrase can be traced back to 16th century Britain, and in the following century the Scottish theologian Samuel Rutherford used the phrase in his argument against the divine right of kings. The rule of law was further popularized in the 19th century by British jurist A. V. Dicey. The concept, if not the phrase, was familiar to ancient philosophers such as Aristotle, who wrote "Law should govern".