Abstract: Abstract. The study examines the notion of "interest" which is widespread in the Russian legislation and scientific publications. It notes that there are different interpretations of the concept of legal interest in law. The notion encompasses the interests of the individual, society and the state. The work focuses on their relationship and manifestation in the implementation of public spending. One of the main criteria which serves as a basis for public expenditure allocation is the nature of interest shown in the planning and implementation of socially important spending. The main method used in the study is a comparative analysis of different points of view on the concept of "interest" and its variants. The study conducted by the author comes to the conclusion that the mentioned examples attest to the relationship between public spending and public interest. The study proves that the public financial and legal interest is of complex nature, it may address the needs of society, state and social group at the same time.