Private law is that part of a civil law legal system which is part of the jus commune that involves relationships between individuals, such as the law of contracts or torts (as it is called in the common law), and the law of obligations (as it is called in civil legal systems). It is to be distinguished from public law, which deals with relationships between both natural and artificial persons (i.e., organizations) and the state, including regulatory statutes, penal law and other law that effects the public order. In general terms, private law involves interactions between private citizens, whereas public law involves interrelations between the state and the general population.

The concept of private law in common law countries is a little more broad, in that it also encompasses private relationships between governments and private individuals or other entities. That is, relationships between governments and individuals based on the law of contract or torts are governed by private law, and are not considered to be within the scope of public law.