Contracting Party

Status Treaty Law Preferred

State that has consented to be bound by a treaty and has become a party to it.

Independent referenceNot an official or legal definition
Sources citedSee the sources at the end of this page
Status Under reviewLast updated 11 October 2026
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Definition

In plain language

A contracting party is a country that has formally agreed to be bound by a treaty. Merely signing a treaty does not always make a country a party.

Academic definition

The Vienna Convention on the Law of Treaties distinguishes a 'contracting State', which has consented to be bound by the treaty whether or not it has entered into force (Article 2(1)(f)), from a 'party', which has consented to be bound and for which the treaty is in force (Article 2(1)(g)). Consent may be expressed by signature, ratification, accession, acceptance or approval (Articles 11 to 16), and a State that has only signed is not a party but must refrain from acts that would defeat the treaty's object and purpose under Article 18. The status carries the treaty's rights and duties and, for multilateral treaties, the right to participate in decisions under the treaty.

Classification

Term type
Status
Category
Treaty Law
Subject field
Treaty Law
Subfield
Parties to Treaties
Difficulty level
Beginner
Grammatical category
noun phrase

Language variants

Alternative terms
  • party to a treaty
  • treaty party
  • contracting State
Non-preferred terms
  • not_applicable
Abbreviations
  • not_applicable
Acronyms
  • not_applicable
Native terms
  • partie contractante (French)
Transliteration
not_applicable
Pronunciation
not_applicable

Context

Legal effect: Binding

Scope

Covers a State's status as bound by a treaty; signatory States, negotiating States and third States are covered in separate records.

Legal context

VCLT Articles 2(1)(f), 2(1)(g), 11 to 16 and 18; Article 34 provides that a treaty does not create obligations or rights for a third State without its consent. The depositary records the date on which a State becomes a party.

Diplomatic context

Lists of parties are maintained by depositaries, and States often press others to become parties to universal conventions.

Institutional context

The UN Secretary-General acts as depositary for many multilateral treaties and publishes status lists in the Treaty Collection.

Historical context

The formal distinction between contracting State and party was drafted by the ILC and fixed in the 1969 Convention.

Why it matters

Whether a State is a party determines which treaty rules apply to it and which courts or monitoring bodies can hold it to account.

Usage

Register: Legal

Usage note

Use 'State party' in human rights treaties and 'contracting party' in older and trade treaties; the meaning is the same.

Example

The country became a contracting party to the convention when it deposited its instrument of ratification.

Example scenario

State A signs a convention in 2020 and ratifies it in 2022. It becomes a party when the convention enters into force for it, and from that date it is bound and can take part in the meetings of parties.

Common misuse

Treating a signatory State as a party; a signatory has not necessarily consented to be bound.

Not to be confused with

  • Signatory state
  • Third State
  • Negotiating State

Sources

  1. Vienna Convention on the Law of Treaties (1969), United Nations, Article 2(1)(f)-(g). legal.un.org
  2. Official definition. not_found_in_source
  3. Treaty reference. legal.un.org
  4. Aust, Modern Treaty Law and Practice. not_found_in_source
  5. not_found_in_source. not_found_in_source

Source type: Treaty. Source reliability: Primary.

This entry is an independent reference definition, not an official or legally binding text. Where an official definition exists, it is linked above and is authoritative. Read our methodology.

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