Government spending or government expenditure is classified by economists into three main types. Government acquisition of goods and services for current use to directly satisfy individual or collective needs of the members of the community is classed as government final consumption expenditure. Government acquisition of goods and services intended to create future benefits, such as infrastructure investment or research spending, is classed as government investment (gross fixed capital formation), which usually is the largest part of the government gross capital formation. Acquisition of goods and services is made through own production by the government (using the government's labour force, fixed assets and purchased goods and services for intermediate consumption) or through purchases of goods and services from market producers. Government expenditures that are not acquisition of goods and services, and instead just represent transfers of money, such as social security payments, are called transfer payments. Government spending can be financed by seigniorage, taxes, or government borrowing.

The first two types of government spending, namely government final consumption expenditure and government gross capital formation, together constitute one of the major components of gross domestic product.

John Maynard Keynes was one of the first economists to advocate government deficit spending as part of the fiscal policy response to an economic contraction. In Keynesian economics, increased government spending is thought to raise aggregate demand and increase consumption.

Classical economists and Austrian economists, however, believe that increased government spending exacerbates an economic contraction by shifting resources from the private sector, which they consider productive, to the public sector, which they consider unproductive. According to Austrian economists, the reason the Great Depression lasted as long as it did was because of significant government spending and government regulation of the economy.