Subject. This article discusses the issues related to the definition of the principles of internal financial control of State (municipal) institutions as the basic provisions of its implementation and organization. Objectives. The article aims to substantiate the composition and define the principles of organization and implementation of internal financial control of State (municipal) institutions, the implementation of which in control activities provides conditions for effective management of institutions. Methods. For the study, we used detailing, observation, generalization, comparison, classification, grouping, etc. Results. Based on the results of a comparative analysis of the distinctive features of internal financial control of State (municipal) institutions from the external one, the article systematizes the well-known approaches to determining the principles of control activities. This helped identify a set of principles of internal financial control of State (municipal) institutions, which form the basis for its effective organization and implementation. Conclusions. The article concludes that there are differences in the composition of the principles of external and internal control, which are associated with the distinctive features of their organization and implementation. The results obtained contribute to the development of theoretical, organizational and methodological provisions of internal financial control.