A municipality’s budget is a tool that significantly affects the long-term economic potential of the area. In addition, it is an important tool for the management of the municipality, in relation to the effective provision of public services for inhabitants. To ensure them, it uses the revenues that the local self-government receives from various sources. The aim of the paper is to characterize and to compare the mechanism of creating revenues of the local self-government in the Slovak and Czech Republic and, at the same time, to analyze the relationships between individual groups of local revenues in the time period 2009–2018. We analyzed the basic groups of municipal revenues: total revenues, current revenues, and capital revenues. For the analysis, we used selected mathematical–statistical methods (trend lines, correlation coefficient). Although both countries were part of one country, both have a dual model of public administration and have undergone fiscal decentralization; the structure and sources of local self-government revenues are different. However, a common attribute is the dependence of local self-government on state revenues. Tax revenues are the most important part of current budget revenues. Despite fiscal decentralization, local budget revenues are dependent on the state. In the Slovak Republic, share taxes from the state represent 74% of the total tax revenues of municipalities, and in the Czech Republic, 85% of the total tax revenues of municipalities.