James O'Brien (August 3, 1836 – May 28, 1903) was a Canadian merchant, wholesaler, and politician.
Born in Aughnagar, County Tyrone, Ireland, O'Brien was educated there and moved to British North America in 1850.
In 1858, he started business in the wholesale clothing and dry goods trade in Montreal.
He was a director of the Montreal City and District Savings Bank, the Royal Victoria Life Insurance Company, and also a member of the Board of Trade.
He was appointed to the Senate representing the senatorial division of Victoria, Quebec on the advice of Mackenzie Bowell on January 2, 1896.