Customary International Law, General Principles of Law, and Other Sources

Research Guides & Background Information

Background Information

Department of State

Research Guides & Background Information


Domestic Law Concerning a Country's International Obligations

Resolutions, Declarations, and Legislative Acts of Intergovernmental

IGO yearbooks


Judicial Decisions of
International Tribunals

Court Decisions of Individual Countries Concerning International Obligations

Scholarly Works

Review Questions

General Principles of Law

Included in the list of sources of international law in Article 38 of the International Court of Justice Statute are “general principles of law recognized by civilized nations” (i.e. general principles of fairness and justice which are applied universally in legal systems around the world). Examples of these general principles of law are laches, good faith, res judicata, and the impartiality of judges. International tribunals rely on these principles when they cannot find authority in other sources of international law.

These general principles of law can be found in decisions of international tribunals and national courts; references to them may also be found in the teachings of the “most highly qualified publicists” (i.e., eminent international law scholars). In fact, Article 38 includes judicial decisions (of both international and municipal tribunals) and scholarly writings as “subsidiary means for the determination of rules of law;” in other words, these are not authorities, rather they are evidence of the sources of international law.