Left-libertarianism, also known as left-wing libertarianism, is a political philosophy and type of libertarianism that stresses both individual freedom and social equality. Left-libertarianism represents several related yet distinct approaches to political and social theory. Its classical usage refers to anti-authoritarian varieties of left-wing politics such as anarchism, especially social anarchism, communalism, and libertarian Marxism, collectively termed libertarian socialism. A portion of the left wing of the green movement, including adherents of Murray Bookchin's social ecology, are also generally considered left-libertarian.

Libertarianism is a political philosophy that upholds liberty as a core value. Libertarians seek to maximize autonomy and political freedom, emphasizing equality before the law and civil rights to freedom of association, freedom of speech, freedom of thought and freedom of choice. Libertarians are often skeptical of or opposed to authority, state power, warfare, militarism and nationalism, but some libertarians diverge on the scope of their opposition to existing economic and political systems. Various schools of libertarian thought offer a range of views regarding the legitimate functions of state and private power. Different categorizations have been used to distinguish various forms of Libertarianism. Scholars distinguish libertarian views on the nature of property and capital, usually along left–right or socialist–capitalist lines. Libertarians of various schools were influenced by liberal ideas.