Sir James Kenneth McLay is a New Zealand diplomat and former politician. He served as the ninth deputy prime minister of New Zealand from 15 March to 26 July 1984. McLay was also Leader of the National Party and Leader of the Opposition from 29 November 1984 to 26 March 1986. Following his ousting as party leader, he retired from parliamentary politics in 1987. In June 2009, he became New Zealand's Permanent Representative to the United Nations. In May 2015, McLay became New Zealand's Representative to the Palestinian Authority. From May 2016 to January 2017, he was New Zealand's Consul General in Honolulu.

The deputy prime minister of New Zealand is the second-most senior member of the Cabinet of New Zealand. The officeholder usually deputises for the prime minister at official functions. The current deputy prime minister is Winston Peters of the NZ First party, who has held the position twice before, and will serve until 31 May 2025 due an arrangement under the current coalition government in which he would then be succeeded in the position by ACT party leader David Seymour.