In economics, supply is the amount of something that firms, consumers, laborers, providers of financial assets, or other economic agents are willing to provide to the marketplace. Supply is often plotted graphically with the quantity provided (the dependent variable) plotted horizontally and the price (the independent variable) plotted vertically.

In microeconomics, supply and demand is an economic model of price determination in a market. It concludes that in a competitive market, the unit price for a particular good, or other traded item such as labor or liquid financial assets, will vary until it settles at a point where the quantity demanded (at the current price) will equal the quantity supplied (at the current price), resulting in an economic equilibrium for price and quantity transacted.