Marja Lehto

Marja Lehto was Ambassador for International Legal Affairs at the Ministry for Foreign Affairs of Finland until her retirement in February 2026.

Over her diplomatic career, she has served in a number of high-level roles, including as Finland’s Ambassador to Luxembourg (2009–2014), Director of the Unit for Public International Law in the Ministry for Foreign Affairs (2000–2009), and Legal Adviser at the Finnish Permanent Mission to the UN in New York (1995–2000). 

She is also Adjunct Professor of International Law at the University of Helsinki, contributing to academia through teaching and research.

Ambassador Lehto was a member of the United Nations International Law Commission and Special Rapporteur for the topic “Protection of the Environment in Relation to Armed Conflicts” from 2017 to 2022. Her work led to the completion and adoption of draft principles on environmental protection in and after armed conflict in 2022. In 2023, she became one of the two recipients of the “Elisabeth Haub Award for Environmental Law and Diplomacy”, recognised for her pivotal role in advancing legal protection for the environment in times of armed conflict. 

She is a Member of the Council of the International Institute of Humanitarian Law since 2019 and currently one of its Vice-Presidents. 

In June 2025, Ambassador Lehto was appointed by Finland as arbitrator at the OSCE Court of Conciliation and Arbitration, and was subsequently elected Vice-President of the Court in January 2026.

Dr. Lehto has published extensively in international law, notably on the law of the sea, use of force, terrorism, environmental law, state responsibility and cyber.