Martti Antero Koskenniemi (born 18 March 1953) is a Finnish international lawyer and former diplomat. Currently he is professor of International Law in the University of Helsinki and Director of the Erik Castrén Institute of International Law and Human Rights, as well as Centennial Professor at the Law Department of the London School of Economics. He is well known for his critical approach to international law. In 2008–2009 he held the seat of distinguished visiting Goodhart Professor at the Faculty of Law, Cambridge University. In 2011 Koskenniemi was Peace of Utrecht professor at Utrecht University. In 2014 he was elected a Corresponding Fellow of the British Academy. Koskenniemi is currently serving as an Academy Professor for the Academy of Finland.