

Public International Law
Allen & Overy advises national and international corporations, financial institutions, international organisations, governments and States on all contentious and non-contentious aspects of public international law. Our market-leading practice includes specialists in environmental law, regulatory compliance and risk management, dispute resolution, anti-bribery and corruption, anti-money laundering, public law, human rights and sanctions.
A&O’s public international law advisory work includes:
- The drafting and interpretation of international treaties and conventions
- Maritime, territorial and boundary rights
- State succession
- International sanctions regimes
- Privileges and immunities of States and international organisations
- Recognition of States and State succession
- Title to natural resources and international environmental law
- Use of force and international humanitarian law
- Space law
- Trade law
We also advise on contentious Public International Law matters, including State-to-State disputes under public international law, including boundary disputes, and have a market-leading investment treaty arbitration practice.
Our experts have acted as counsel before international courts and special tribunals, such as the Iran-US Claims Tribunal, and advised states on out-of-court strategies for dispute resolution, including before UN fora. We are also one of only a handful of law firms with experience of contentious World Trade Organisation proceedings.
Explore our services
News and insights

Publications: 02 February 2023
Podcast: Sanctions outlook 2023
Sanctions began dominating the headlines again in 2022. Largely, reports focused on the ongoing sanctions targeting Russia. As we look ahead to 2023, Russia remains a target. Other countries (such as…

Publications: 29 November 2022
The U.N. Human Rights Committee ruled in a watershed case that Australia has failed adequately to protect indigenous Torres Strait Islanders from the adverse effects of climate change.

Publications: 25 February 2022
EU and UK sanctions in response to Russia’s actions in Ukraine
In response to the Russian Federation’s formal recognition of two regions in Eastern Ukraine – Donetsk and Luhansk – as independent states, earlier this week the EU and the UK adopted an initial…

Publications: 21 February 2022
Webinar: International sanctions update 2022
Sanctions developments are grabbing headlines around the globe with the spotlight recently focused on Russia and Ukraine and the media dubbing the USA’s potential response “the mother of all…
Awards and achievements
- Tier One, Public International Law, Legal 500 UK 2022
- Band 1, Dispute Resolution, Global: Multi-Jurisdictional,, Chambers Global 2022
- International Arbitration Firm of the Year, Benchmark Litigation Asia-Pacific Awards 2020
- Leading firm (top tier) ranking in the “Leaders League” table for International Arbitration (Spain) 2022
Recognition
Strong track record in representing sovereign states and corporates in high-value investment treaty disputes. Considerable experience carrying out its own advocacy before courts and tribunals. Also adept at handling a number of other public international law matters, such as ECT claims, WTO cases, sovereign immunity concerns, and international treaty drafting and negotiation.
Chambers UK 2022, Public International Law
The team has incredible breadth and expertise in public international law. I have always been impressed by the quality of their work and their excellent reputation is well deserved
Legal 500 UK 2021, Public International Law
Allen & Overy LLP has superlative expertise across the full spectrum of public international law and related matters… Its 'outstanding and hardworking' team is experienced in state-to-state disputes before the International Court of Justice and tribunals under the jurisdiction of the Permanent Court of Arbitration, ICSID, the United Nations Convention for the Law of the Sea and other ad hoc bodies.
Legal 500 UK 2019, Public International Law
Has a great deal of experience acting for both claimants and respondents in investment treaty disputes…Wins further recognition for its thriving sanctions practice and expert advice on sovereign immunity, Energy Charter Treaty claims, WTO matters and EU law.
Chambers Global 2020, Public International Law
Highly regarded for its expertise in investment treaty arbitrations. Experienced in arbitrations acting both for and against sovereign states and government bodies.
Chambers Asia-Pacific 2020, International Arbitration, China
Highly rated for its skilful handling of investment treaty disputes on behalf of both sovereigns and investors.
Chambers Global 2019, Public International Law
Related content

International Arbitration Review
Recent developments and emerging trends in international arbitration law and policy