Egalitarianism (from French égal 'equal'), or equalitarianism, is a school of thought within political philosophy that builds on the concept of social equality, prioritizing it for all people. Egalitarian doctrines are generally characterized by the idea that all humans are equal in fundamental worth or moral status. Egalitarianism is the doctrine that all citizens of a state should be accorded exactly equal rights. Egalitarian doctrines have motivated many modern social movements and ideas, including the Enlightenment, feminism, civil rights, and international human rights.

The term egalitarianism has two distinct definitions in modern English, either as a political doctrine that all people should be treated as equals and have the same political, economic, social and civil rights, or as a social philosophy advocating the removal of economic inequalities among people, economic egalitarianism, or the decentralization of power. Sources define egalitarianism as equality reflecting the natural state of humanity.