Government Expenditure impacts on the economic system through different layers. The challenge for government agencies is not only to get their role right but also to limit their interventions within a threshold based on the level of the country’s economic development. In recent years, there has been a growing interest in government agriculture expenditure (GAE) in developing countries. Many academics set out to analyze agricultural public spending or its impact on agricultural GDP or GDP. This study aimed to investigate the determinants of government agriculture expenditure (GAE) in Haiti from 2007 to 2020. This study also presented the magnitude and type of relationship between public agricultural expenditure and other literature-suggested factors. It also looked at the composition of agricultural public expenditure, namely agricultural investment expenditure and agricultural operating expenditure according to Aschauer's theory (1989). The paper considered government agriculture expenditure as an endogenous variable according to Wagner's law (1883). Confirmatory Unit root test and OLS Estimators were used as an empirical approach. The results showed that agricultural GDP has a statistically significant impact on government agriculture expenditure in Haiti, and the effect is significant at a 5% level of error. The results also showed that government investment in agriculture and government consumption in agriculture have a statistically significant impact on government agriculture expenditure in Haiti, and the effect is significant at a 1% level of error. The size of the coefficient is greater for agricultural GDP compared to government investment in agriculture and government consumption in agriculture since agriculture value added reflects the performance of agriculture. However, the size of the coefficient is greater for government consumption in agriculture than government investment in agriculture, which is not consistent with the literature review since investment expenditures in agriculture are productive expenditures that boost the agriculture sector.