William James "Jim" Riordan (20 April 1882 – 15 September 1955) was an Australian politician. He was born in Mackay to William Riordan and Mary, née Walsh. After attending Mackay State School he became a labourer on the Cairns–Mulgrave railway line and then a fireman for the Chillagoe Railway Company. While there he became President of the Chillagoe Amalgamated Workers' Union and in 1903 an organiser with the Far North Australia Workers' Union (FNAWU). On 28 March 1907 he married Annie Helen Page, with whom he had a son and two daughters. In 1916 he became state president of the FNAWU, and in 1917 was appointed to the Queensland Legislative Council for the Labor Party. Riordan served in the Council until its abolition, according to Labor policy, in 1922. In 1925 he moved from president to secretary of the FNAWU, a position he held until 1933 when he was appointed to the Queensland Industrial Court. He was also involved in the Labor press as director of The Daily Standard and The Worker, which were published in Brisbane. He served on the court until 1953, and from 1951 to 1952 was chairman of the Royal Commission on Offcourse Betting. He had remarried, to Lyla Elizabeth Boland on 2 October 1943. He died in Brisbane in 1955 and was buried in Lutwyche Cemetery.