Sir Kenneth James Keith ONZ KBE KC PC (born 19 November 1937)^[1] is a New Zealand judge. He was elected to the International Court of Justice in November 2005, serving a nine-year term during the years 2006 through 2015.^[2]

Keith was educated at the Auckland Grammar School and studied law at the University of Auckland, Victoria University of Wellington, and Harvard Law School. He was a faculty member of Victoria University from 1962 to 1964 and from 1966 to 1991. He served in the New Zealand Department of External Affairs during the early 1960s, and as a member of the United Nations Secretariat from 1968 to 1970. After this, he was Director of the New Zealand Institute of International Affairs^[3][4] and later became President of the New Zealand Law Commission. He was also a member of the Royal Commission on the Electoral System which was key in changing New Zealand's electoral system. In 1993 he was a member of the Working Party on the Reorganisation of the Income Tax Act 1976 which was instrumental in launching a fundamental reform the way New Zealand tax legislation was written.

From 1996 to 2003, Keith was a Judge of the Court of Appeal of New Zealand and was a member of the Judicial Committee of the Privy Council in London. He was subsequently one of the inaugural appointments to the new Supreme Court of New Zealand which replaced the Judicial Committee of the Privy Council as from 1 July 2004. Prior to his appointment to the International Court of Justice, he sat (as required) as a Judge of Appeal in Samoa (since 1982), the Cook Islands (since 1982) and Niue (since 1995), and Judge of the Supreme Court of Fiji. He has also sat as the chair of a North American Free Trade Agreement (NAFTA) Tribunal (UPS v Canada).

In 1961, Keith was admitted to the New Zealand Bar, and in 1994 appointed a Queen's Counsel.^[5] In 1996 Keith was appointed as a Judge of High Court of New Zealand and the Court of Appeal of New Zealand^[6] On 21 May 1998 Keith was appointed to the Privy Council^[7] and in 2004 was appointed to the Supreme Court of New Zealand.^[8]

Keith is the first New Zealander to be elected to the International Court of Justice (2006–2015), having previously presented as a member of the New Zealand legal team in the Nuclear Tests cases before the International Court of Justice in 1973, 1974 and 1995.^[9]

He recently served as a Judge ad hoc in two cases before the ICJ, appointed by Azerbaijan. He resigned from these positions on April 21, 2023, and was replaced by Judge Abdul G. Koroma. ^[10]

In the 1988 Queen's Birthday Honours, Keith was appointed a Knight Commander of the Order of the British Empire, for services to law reform and legal education,^[11] and in the 2007 Queen's Birthday Honours he was appointed a Member of the Order of New Zealand.^[12][13]

• Interpreting in International Courts and Tribunals in the Lecture Series of the United Nations Audiovisual Library of International Law
• The International Court of Justice – The Reflections of One Judge as He Leaves Office in the Lecture Series of the United Nations Audiovisual Library of International Law
• Openness in International Law in the Lecture Series of the United Nations Audiovisual Library of International Law
• Asia and International Law: A New Era Distinguished Speakers Panel in the Lecture Series of the United Nations Audiovisual Library of International Law
• Aspects of the Judicial Process in National and International Courts and Tribunals in the Lecture Series of the United Nations Audiovisual Library of International Law
• The Rainbow Warrior Case in the Lecture Series of the United Nations Audiovisual Library of International Law
• The Role of International Law in National Law in the Lecture Series of the United Nations Audiovisual Library of International Law
• The International Court of Justice and criminal justice in the Lecture Series of the United Nations Audiovisual Library of International Law
• The International Court of Justice - The Reflections of One Judge as He Leaves Office in the Lecture Series of the United Nations Audiovisual Library of International Law
• Interpreting in International Courts and Tribunals in the Lecture Series of the United Nations Audiovisual Library of International Law