Samuel Jacob Jackson (February 18, 1848 – May 29, 1942) was a Canadian politician.
Born in Stradbally, Queen's County, Ireland, the son of Samuel Jackson and Elizabeth Sutcliffe, Jackson was educated at Brantford, Ontario. He came west to Manitoba in 1871. Jackson later became a partner in a mercantile firm in Winnipeg. In 1878, he married Ida Isabella Clark. Jackson later moved to Stonewall, where he was a merchant and mill owner.
He was elected to the Legislative Assembly of Manitoba for the electoral district of Rockwood in 1883, 1884, 1886, 1888, 1892 and 1896. He was defeated in 1899. From 1891 to 1895, he was the Speaker of the Legislative Assembly.
He was first returned to Canadian House of Commons in the general elections of 1904 for the riding of Selkirk. A Liberal, he was defeated in 1908. He was an Alderman in the Winnipeg City Council in 1877, 1878 and 1880. Jackson was chairman of the Board of Works for Winnipeg in 1882.