This work is devoted to the study of the law nature and main features of the institution of public-private partnership (hereinafter – PPP), to identify its relationship and relationship with the concept of public-private interaction. In a market economy the institute of public-private partnership allows the state to use flexible mechanisms to achieve socially significant goals. The PPP ensures the participation of individuals in solving public problems and at the same time guarantees that businesses receive economic benefits from such participation. The key aspect and main problem of PPP is the search for an optimal model of legal regulation, which is inextricably linked with the understanding of the legal nature of this institution.