pacta sunt servanda

law principle

Written by

The Information Architects of Encyclopaedia Britannica

Last updated

July 16, 2026

Quick Summary

Pacta sunt servanda is a fundamental principle of international law, meaning "agreements must be kept". This concept underscores the binding nature of treaties and international agreements. Without this principle, no international agreement would be enforceable.1

Treaties, also known as conventions, agreements, or pacts, are written instruments where parties agree to be bound by negotiated terms. These can be bilateral or multilateral and are crucial for establishing international law. The principle of pacta sunt servanda is explicitly referenced in international agreements governing treaties, such as the Vienna Convention on the Law of Treaties.1

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

4 Britannica Sources

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.

international law
Treaties
…known by the Latin formula pacta sunt servanda (“agreements must be kept”) is arguably the oldest principle of international law. Without such a rule, no international agreement would be binding or enforceable. Pacta sunt servanda is directly referred to in many international agreements governing treaties, including the Vienna Convention on…
Read More
…known by the Latin formula pacta sunt servanda (“agreements must be kept”) is arguably the oldest principle of international law. Without such a rule, no international agreement would be binding or enforceable. Pacta sunt servanda is directly referred to in many international agreements governing treaties, including the Vienna Convention on…
Read More

treaty
…keeping with the principle of pacta sunt servanda (Latin: “agreements must be kept”), arguably the oldest principle of international law. Without this principle, which is explicitly mentioned in many agreements, treaties would be neither binding nor enforceable.
Read More
…keeping with the principle of pacta sunt servanda (Latin: “agreements must be kept”), arguably the oldest principle of international law. Without this principle, which is explicitly mentioned in many agreements, treaties would be neither binding nor enforceable.
Read More