Sir James Long, 5th Baronet (1682 – 16 March 1729) was an English politician.
The son of James Long and his wife Susan Strangways, he was born at Athelhampton and baptised at Melbury House, Dorchester, Dorset in 1682. Long was Member of Parliament for Chippenham in 1705, 1707, 1708, and 1710, and for Wootton Bassett in 1714. He was the grandson of Sir James Long, 2nd Baronet and brother of the celebrated Kit-Cat Club beauty Anne Long (c.1681-1711).
He succeeded to the baronetcy on the death of his brother Sir Giles Long, 4th Baronet, in 1698. On the death of his grandmother Lady Dorothy Long in 1710, he inherited the Draycot Estate together with Athelhampton Manor, other land in Wiltshire and Dorset, and an estate near Ripon in Yorkshire. He used the inheritance to purchase more land in Dorset, adjacent to Athelhampton, in the manors of Burleston and Southover.
He married Henrietta Greville on 6 June 1702 at St Martin in the Fields, Westminster, London. She was the daughter of Fulke Greville, 5th Baron Brooke and his wife Sarah Dashwood, and a descendant of the Earl of Bedford. There were four daughters and two sons from this marriage, including Sir Robert Long, 6th Baronet.