Socialist law denotes a general type of legal system which has been used in communist and formerly communist states. It is based on the civil law system, with major modifications and additions from Marxist-Leninist ideology. There is controversy as to whether socialist law ever constituted a separate legal system or not. If so, prior to the end of the Cold War, socialist law would be ranked among the major legal systems of the world.

While civil law systems have traditionally put great pains in defining the notion of private property, how it may be acquired, transferred, or lost, socialist law systems provide for most property to be owned by the state or by agricultural co-operatives, and having special courts and laws for state enterprises.^{[citation needed]}

Many scholars argue that socialist law was not a separate legal classification. Although the command economy approach of the communist states meant that most types of property could not be owned, the Soviet Union always had a civil code, courts that interpreted this civil code, and a civil law approach to legal reasoning (thus, both legal process and legal reasoning were largely analogous to the French or German civil code system). Legal systems in all socialist states preserved formal criteria of the Romano-Germanic civil law; for this reason, law theorists in post-socialist states usually consider the Socialist law as a particular case of the Romano-Germanic civil law. Cases of development of common law into Socialist law are unknown because of incompatibility of basic principles of these two systems (common law presumes influential rule-making role of courts while courts in socialist states play a dependent role).^{[citation needed]}