Classical Liberalism (sometimes called English Liberalism) is a political tradition and a branch of liberalism that advocates free market and laissez-faire economics and civil liberties under the rule of law, with special emphasis on individual autonomy, limited government, economic freedom, political freedom and freedom of speech. Classical liberalism, contrary to liberal branches like social liberalism, looks more negatively on social policies, taxation and the state involvement in the lives of individuals, and it advocates deregulation.

Until the Great Depression and the rise of social liberalism, classical liberalism was called economic liberalism. Later, the term was applied as a retronym, to distinguish earlier 19th-century liberalism from social liberalism. By modern standards, in the United States, the bare term liberalism often means social or progressive liberalism, but in Europe and Australia, the bare term liberalism often means classical liberalism.

Classical liberalism developed in the early 18th century, building on ideas dating back to the 16th century, and was foundational to the American Revolution and the "American Project" more broadly. Notable liberal individuals whose ideas contributed to classical liberalism include John Locke, François Quesnay, Jean-Baptiste Say, Montesquieu, Voltaire, Marquis de Condorcet, Thomas Paine, Thomas Malthus, and David Ricardo. It drew on classical economics, especially the economic ideas espoused by Adam Smith in Book One of The Wealth of Nations, and on a belief in natural law. In contemporary times, Murray Rothbard, Friedrich Hayek, Milton Friedman, Ludwig von Mises, Thomas Sowell, Walter E. Williams, George Stigler, Larry Arnhart, Ronald Coase and James M. Buchanan are seen as the most prominent advocates of classical liberalism. However, other scholars have made reference to these contemporary thoughts as neoclassical liberalism, distinguishing them from 18th-century classical liberalism.

In its defense of economic liberties, classical liberalism may be described as conservative or right wing, though classical liberals tend to reject the right's higher tolerance for economic protectionism. Conversely, in its defense of civil liberties, it has more in common with modern liberalism (the left), though classical liberalism tends to reject the left's inclination for collective group rights due to its central principle of individualism. Additionally, in the United States, classical liberalism is considered closely tied to, or synonymous with, American libertarianism.

Core beliefs of classical liberals included new ideas – which departed from both the older conservative idea of society as a family and from the later sociological concept of society as a complex set of social networks.

Classical liberals agreed with Thomas Hobbes that individuals created government to protect themselves from each other and to minimize conflict between individuals that would otherwise arise in a state of nature. These beliefs were complemented by a belief that financial incentive could best motivate labourers. This belief led to the passage of the Poor Law Amendment Act 1834, which limited the provision of social assistance, based on the idea that markets are the mechanism that most efficiently leads to wealth.

Drawing on ideas of Adam Smith, classical liberals believed that it was in the common interest that all individuals be able to secure their own economic self-interest. They were critical of what would come to be the idea of the welfare state as interfering in a free market. Despite Smith's resolute recognition of the importance and value of labour and of labourers, classical liberals criticized labour's group rights being pursued at the expense of individual rights while accepting corporations' rights, which led to inequality of bargaining power. Classical liberals argued that individuals should be free to obtain work from the highest-paying employers, while the profit motive would ensure that products that people desired were produced at prices they would pay. In a free market, both labour and capital would receive the greatest possible reward, while production would be organized efficiently to meet consumer demand. Classical liberals argued for what they called a minimal state and government, limited to the following functions:

Classical liberals asserted that rights are of a negative nature and therefore stipulate that other individuals and governments are to refrain from interfering with the free market, opposing social liberals who assert that individuals have positive rights, such as the right to vote, the right to an education, the right to healthcare, and the right to a minimum wage. For society to guarantee positive rights, it requires taxation over and above the minimum needed to enforce negative rights.