A tax is a compulsory financial charge or some other type of levy imposed on a taxpayer (an individual or legal entity) by a governmental organization in order to fund government spending and various public expenditures. A failure to pay, along with evasion of or resistance to taxation, is punishable by law. Taxes consist of direct or indirect taxes and may be paid in money or as its labour equivalent. The first known taxation took place in Ancient Egypt around 3000–2800 BC.

Most countries have a tax system in place, in order to pay for public, common, or agreed national needs and for the functions of government. Some levy a flat percentage rate of taxation on personal annual income, but most scale taxes are progressive based on brackets of annual income amounts. Most countries charge a tax on an individual's income as well as on corporate income. Countries or subunits often also impose wealth taxes, inheritance taxes, estate taxes, gift taxes, property taxes, sales taxes, use taxes, payroll taxes, duties and/or tariffs.

In economic terms, taxation transfers wealth from households or businesses to the government. This has effects that can both increase and reduce economic growth and economic welfare. Consequently, taxation is a highly debated topic.