The article examines the role of the judiciary in implementing the principle of separation of powers in the budget process of Ukraine in the context of current legislation. The object of the study is a set of social relations that are formed in the field of consolidation and implementation of the constitutional principle of separation of powers in the activities of local state authorities in the budget process. The subject of the study is constitutional and legal norms and norms of budget legislation. The methodological basis was made up of general scientific and special-legal (formal-legal, comparative-legal, systemic and other) methods of cognition. It is noted that the constitutional principle of the separation of powers in the budget process is an interpectoral normative requirement for the activities of representative and local executive bodies, which independently and in cooperation with each other in certain forms and procedures participate in the budget process. In this, judicial authorities are called upon to guarantee, within their competence, the distribution of budgetary powers between representative and local executive bodies. The relationship between the representative and executive bodies of state power in the budget process is shown, which determines the need for systematic support for the implementation of the constitutional principle of separation of powers in the budget process through the formation of the construction of the mechanism for such support.
 The design of the mechanism for ensuring the implementation of the constitutional principle of separation of powers in the budget process has three interrelated elements: an organizational and legal element; institutional element; procedural element. Representative bodies and local executive bodies determine consistent implementation of the constitutional principle of separation of powers in the budget process carried out by local authorities. It is indicated that the judicial authorities in the implementation of the constitutional principle of separation of powers in the budget process guarantee and ensure the implementation of this principle in the form of: resolution of legal disputes; judicial control in the field of budgetary relations; independent assessment of law enforcement decisions of local authorities – participants in the budget process.