James Christian Lang (25 March 1910 – 14 December 2002) was an Australian politician. The son of Jack Lang, Premier of New South Wales 1925–27 and 1930–32, he succeeded his father as the member for Auburn in the New South Wales Legislative Assembly, serving from 1946 to 1950.
Born in Homebush, Lang was educated at North Auburn Public School and Burwood Intermediate High School before entering his father's real estate business, Lang and Daes, in 1925. In 1930 he became the manager, remaining so until 1958, when he became the manager of his own real estate company until 1962. On 22 February 1933 he married Mary Dowling, with whom he had three children. He also served as secretary of the Auburn Starr-Bowkett Co-operative Building Societies.
In 1946, Jack Lang resigned from state parliament to run for the federal seat of Reid, prompting a by-election for the state seat of Auburn. By this time both the federal and state branches of the Australian Labor Party had repudiated the former Premier, who endorsed his son to run under the Lang Labor banner. Lang was successful, achieving 52.32% of the primary vote and easily defeating the official Labor candidate (helped by the absence of a Liberal candidate). He thus joined Lilian Fowler as one of two Lang Labor MPs.
Lang was forced to preferences at the 1947 state election, when independent Alexander Kerr won 22.2%; despite the fact that the majority of these preferences flowed to official Labor, Lang's primary vote lead was enough to retain the seat. In 1950, however, there was a redistribution, and the sitting Labor MP for the rural abolished seat of Ashburnham, Edgar Dring, contested the new seat. By this time, Lang Labor was dying out (Jack Lang had lost his federal seat the previous year), and Lang was effectively an independent Labor candidate. The Liberal Party contested the seat, with the result that Dring easily defeated Lang. Lang contested Auburn again in 1953 and 1956, but never came close to winning.