This study has evaluated the causality between public expenditures and economic growth within the framework of Wagner’s Law and Keynes’s Hypothesis, by putting forth the development of public expenditures in Turkey for the period of 1980-2010. It was aimed to put forth the importance of public expenditures for the Turkish economy through investigating the relations of public expenditures with economic growth by using the models that are related to Wagner’s Law. In study econometric analyses are performed by using public expenditures and GDP annually. In this context, relationships between these variables are revealed by using ADF unit-root test, Toda and Yamamoto causality test and dynamic least squares method. Analyses are performed in the context of models of Peacock-Wiseman, Goffman-Mahar, Gupta-Michas, Mann and Payne-Ewing which consider Wagner’s Law. As a result of analyses, a causality relation was not found between public expenditures in terms of Peacock-Wiseman model and although the Wagner’s Law and Keynes’s Hypothesis are valid in Turkish economy with regrad to other four models. According to cointegration test results, it is concluded that Wagner’s Law is valid