Political philosophy, also known as political theory, is the study of topics such as politics, liberty, justice, property, rights, law, and the enforcement of laws by authority: what they are, if they are needed, what makes a government legitimate, what rights and freedoms it should protect, what form it should take, what the law is, and what duties citizens owe to a legitimate government, if any, and when it may be legitimately overthrown, if ever.

In a vernacular sense, the term “political philosophy” often refers to a general view, or specific ethic, political belief or attitude, about politics, synonymous to the term “political ideology”.

Political philosophy is a branch of philosophy. Within political science, a strong focus has historically been placed on the role of political philosophy (also known as normative theory), moral philosophy and the humanities, although in recent years there has been increased focus to political theory based on quantitative methodological approaches as well as economic theory, the natural sciences and behaviouralism.