James O’Brien (1875 – 28 September 1947) was a New Zealand politician of the Labour Party.
He represented the Westland seat in Parliament from 1922, when he defeated Tom Seddon. He lost the seat in 1925 to Tom Seddon, but won it back in 1928, and held it to 1947, when he died.
He was a Minister from 1942 to 1947 in the First Labour Government.
New Zealand Parliamentary Record 1840-1984 by J. O. Wilson (1985, Government Printer, Wellington)