Sebastian Stewart Dickinson (25 March 1815 – 23 August 1878) was an English Liberal Party politician who sat in the House of Commons from 1868 to 1874.
Dickinson was the son of Major General Thomas Dickinson, of the Honourable East India Company's Engineers, and of Hurstpierpoint. He was educated at Eton College and was called to the bar at the Inner Temple in June 1839. He was chairman of Board of Guardians at Stroud, and chairman of 2nd Court of Quarter Sessions for Gloucestershire. He was a J.P. for Gloucestershire and a captain in the 5th Gloucestershire Rifle Volunteers. He was also a Fellow of the Heraldry Society and a Fellow of the Royal Geographical Society.
At the 1868 general election Dickinson was elected as a Member of Parliament (MP) for Stroud. He was re-elected at the 1874 general election, but in April 1874 his election was declared void.
Dickinson married Frances Stephana Hyett, daughter of William Henry Hyett of Painswick House, Gloucestershire in 1856. He died at the age of 63.