Sir Arnold Henry Nordmeyer, ONZ, KCMG (7 February 1901 – 2 February 1989), born Heinrich Arnold Nordmeyer, was a New Zealand politician. He was leader of the Labour Party for three years while it was in Opposition.

Nordmeyer was born on 7 February 1901 in Dunedin, New Zealand. His father was a German immigrant, his mother was from Northern Ireland. He was educated at Waitaki Boys' High School, and at the University of Otago where he completed his BA. After graduating he studied theology, having always been highly religious. At university he became known for his skills in debating which were to serve him well in his later career. Although he did not join the Labour Party until 1933, he became increasingly sympathetic to the party's views. It was at this time that he met Walter Nash who may have been influential in shaping his views in health and social policy. In 1925 Nordmeyer received his ordination as a Presbyterian minister and was appointed to a position in the small town of Kurow.

While in Kurow during the Great Depression, Nordmeyer became interested in the welfare of workers involved in the construction of a hydroelectric dam on the Waitaki River. He became increasingly politically active as a result witnessing both the working conditions of the labourers and the poor living conditions of the unemployed men and their families who were attracted to the area by the promise of work. At Kurow, Nordmeyer, along with local doctor and future Labour MP Gervan McMillan and school headmaster Andrew Davidson developed ideas of how to apply Christian ethics to politics to solve the miseries of unemployment, poverty and illness – ideas that were later implemented by the First Labour Government of New Zealand. It was also in Kurow that Nordmeyer met his future wife, Frances Kernahan who he married in 1931.