Armey Curve, propounded by Richard Armey, is one of the tools that developed to demonstrate the role of the state in the economic process. The basic logic behind the Armey Curve is that the relationship between public spending and gross domestic product (GDP) is positive up to a certain point, thereafter the relationship becomes negative. According to Friedman (1997), the government has an important role in a free and open society. It is emphasized that, average contribution of the public sector in the economy is positive, but as the public share of national income increases from 15% to 50% the marginal contribution of the public sector will be negative. Therefore, Friedman advocates that based on development level of countries, the optimal level of public spending should be between 15% and 50%. In this article, Friedmanís hypothesis is tested for Turkish economy using the data of the period 1975-2010 by the help of econometric timeseries analysis, and Armey Curve is evaluated whether it is valid for total public expenditure and expenditure components or not. Empirical findings confirmed that there is a relationship as "inverse U" between economic growth and other expenditure components except public investment expenditure. Moreover, the optimal level of total public expenditure for Turkish economy is calculated as 16% of GDP. This ratio is below the level of 26.6% which is the ratio of 2010 public expenditure to GDP. In this case, one of the macroeconomic policy proposals can be the reduction of the public expenditures in Turkish economy.
Public Sector, Armey Curve, Friedman\'s Hypothesis, Co-integration. JEL Classification: C10, C51, H50, O40.