Education plays a major role in the development of the country. The government allocation of the education expenditure has determined by some variables. The government has some complicated issues for dividing expenditure among all educational factors. The purpose of this study builds on the established theories of public policy analysis, economics, and public finance to empirically investigate and analyse the determinants of public expenditure on education in Sri Lanka. In this study, the empirical results are presented for an equation using the time-series data for 36 years, from 1980 to 2015. For this analysis, Eviwes 8 statistical package was used. The findings of the research show the following result. Gross domestic product is positive and it is significant, indicating that GDP positively determines the total expenditure on education in Sri Lanka number of government Schools (GS) has an insignificant and negative coefficient, Number of government school students (GSS) and a number of government teachers (GST) also has a significant and positive coefficient. That seems to significantly determine the total educational expenditure. The results seem to send a signal that policymakers hardly take into account the above factors in policies.