Sir James Peter Quilliam (23 March 1920 – 17 February 2004) was a New Zealand lawyer and jurist. He served as Chief Justice of the Cook Islands and a judge of the High Court of New Zealand.

Born in New Plymouth on 23 March 1920, Quilliam was educated at Wanganui Collegiate School.^[1] He went on to study at Canterbury University College from 1938 to 1940, and Victoria University College from 1941 to 1943, graduating from the latter with an LLB degree in 1943.^[1][2] He saw military service as a lieutenant with the 2nd New Zealand Expeditionary Force in Fiji between 1942 and 1943.^[1]

In 1945, Quilliam married Ellison Jean Gill, and the couple went on to have three children.^[1]

Quilliam was admitted as a barrister and solicitor in 1944,^[1] and practised law in New Plymouth.^[2] Between 1955 and 1969, he was the New Plymouth Crown solicitor.^[1]

Between 1969 and 1988, Quilliam served as a judge of the High Court (known as the Supreme Court at the time of his appointment).^[1] In the 1988 New Year Honours, he was appointed a Knight Bachelor.^[3] Quilliam became the inaugural head of New Zealand's Police Complaints Authority (now the Independent Police Conduct Authority) in 1989, and served in that capacity until 1992.^[1][2]

In 1988, Quilliam became a judge of the Cook Islands High Court and Court of Appeal, and Chief Justice of the Cook Islands in 1995.^[1] He was also appointed a judge of the Court of Appeal of Fiji in 1992.^[1]