A Dictionary of the World's Legal Systems: Civil Law, Common Law, and More

The word "law" means the same thing everywhere, but how it actually works differs from country to country. Explore 5 legal systems around the world, along with their origins.

Civil Law (World's two major legal systems)

Origin: A legal tradition rooted in ancient Roman law, later systematized through France's Napoleonic Code (1804) and Germany's Civil Code (BGB), among others. Feature: Civil law treats a written legal code enacted by the legislature as the primary source of law, with judges playing the role of interpreting and applying that code. Past rulings (precedent) can serve as a reference but generally carry only weak binding force over lower courts. Representative countries: Korea, Japan, France, Germany, China, and many other countries across continental Europe and Asia.

Common Law (World's two major legal systems)

Origin: A legal tradition formed through the accumulation of rulings by England's royal courts from the 11th century onward, later spreading to Britain's colonies and spheres of influence. Feature: A court's accumulated body of precedent (prior rulings) serves as an important source of law, and under the "principle of stare decisis," a higher court's ruling binds the handling of similar cases afterward. Written statutes also exist, but the shaping of legal doctrine through precedent occupies a large share. Representative countries: the United Kingdom, the United States, Canada, Australia, India, Singapore, and others.

Islamic Law (Sharia)

Origin: A religious normative system based on the Quran, Islam's holy scripture, and the Hadith, the record of the Prophet Muhammad's sayings and actions. Feature: It is distinctive in that it can broadly govern not only faith and ritual but also family matters, inheritance, contracts, and criminal issues. Its actual scope and intensity of application vary greatly by country, ranging from nations that reflect it only partially, in areas like family law, to nations that apply it comprehensively, including criminal law. Representative countries: applied broadly in some countries such as Saudi Arabia and Iran; reflected only in a limited way, such as in family law, in many other Muslim-majority countries.

Customary Law

Origin: Arises from unwritten practices repeated over a long period within a particular community, which its members come to accept as something that "naturally must be followed." Feature: It is distinctive in that it carries normative force through the shared understanding of community members alone, without any separate legislative procedure. Today it tends to function less as an independent system and more as a complement alongside a nation's written law, especially in matters of land and family. Representative regions: various parts of sub-Saharan Africa, traditional communities in Pacific island nations, and others.

Mixed (Pluralistic) Legal System

Origin: Formed when two or three different legal traditions come to exist side by side within a single country, for historical reasons such as colonial rule or political upheaval. Feature: A representative form is one in which civil law and common law are used together, or in which secular law and religious law are applied to separate domains. Understanding which tradition applies to which domain is the starting point for understanding a given country's legal system. Representative countries: South Africa, Scotland, and the Philippines (civil law + common law); Malaysia and Indonesia (secular law + Islamic law), among others.

Can a single country have more than one legal system?

Yes — this is called a "mixed legal system." It is not uncommon for two or three different legal traditions to divide up domains and be used together within a single country, shaped by a history of colonial rule, religious background, or political change. For example, religious law might apply to family law while civil or common law applies to commercial or criminal law.

Where does Korea fall among these legal systems?

Korea is closer to the civil law tradition, treating the written legal code enacted by the National Assembly as its primary source of law. That said, given how much practical influence the Constitutional Court's unconstitutionality rulings and Supreme Court precedents carry, some assess that the weight given to precedent has been gradually growing, beyond a purely code-based approach.

Frequently Asked Questions

Do common law countries also have written statutes?

Yes, common law countries also have many written statutes enacted by their legislatures. The key difference, however, is that when interpreting how to apply those statutes to an actual case, prior precedent carries far greater binding force than it does in civil law countries.

Do you also cover legal terms often heard in the news?

Yes — if you're curious about everyday legal terms like plaintiff/defendant or indictment/non-indictment, take a look at our dictionary of everyday legal terms as well.