What Is the Vienna Convention on the Law of Treaties?
The Vienna Convention on the Law of Treaties is a multilateral international law convention codifying rules on concluding, applying and interpreting treaties between states.
Also known as: VCLT, Vienna Convention (1969).
How Vienna Convention on the Law of Treaties works
The Vienna Convention on the Law of Treaties applies when a treaty between states, including a double tax treaty, has to be performed or interpreted, and the convention requires good-faith performance and reading the text by its ordinary meaning in context and in light of its object and purpose. Supplementary means, such as preparatory work, may confirm or clarify a meaning. Courts and tax authorities often refer to the convention as customary international law, even for states which have not ratified the convention. Domestic rules on how treaties take effect still vary, so the practical weight of treaty interpretation differs by country.
Vienna Convention on the Law of Treaties vs OECD Model Convention
Unlike the OECD Model Convention, which is a template for drafting tax treaties, the Vienna Convention on the Law of Treaties sets general rules on how any treaty is performed and interpreted.
Example
Illustrative example: Country A and Country B disagree on whether a remote worker's fees fall under the business profits article of a treaty between the two countries. Both competent authorities start from the ordinary meaning of the treaty terms in context, as the Vienna Convention requires, before consulting commentaries as supplementary material.
Common misconception
Myth: Tax treaties can be read word by word in whichever way gives the lowest tax.
Reality: Under the Vienna Convention on the Law of Treaties, treaty terms are read in good faith, in context and in light of the treaty's object and purpose, which generally includes preventing abuse.
Frequently asked questions
What is the Vienna Convention on the Law of Treaties?
The Vienna Convention on the Law of Treaties is the 1969 convention codifying how treaties between states are concluded, performed in good faith and interpreted.
Does the Vienna Convention apply to tax treaties?
Double tax treaties are treaties between states, so courts and tax authorities generally apply the interpretation rules of the Vienna Convention on the Law of Treaties to them, subject to domestic law.
Related terms
- Multilateral Instrument (MLI) — Treaty modifying tax treaties, read under VCLT rules
Related guides
- Tax treaties and international taxation — Overview of how tax treaties operate
Sources
Last verified: 2026-10-09. This entry is general information, not tax or legal advice; rules vary by country and change over time.
