Brian Fairfax (1633–1711) was an English politician.
Brian Fairfax, the second son of the Rev. Henry Fairfax, was born at the rectory at Newton Kyme, Yorkshire, on 6 October 1633. He gives some account of his early life in a manuscript narrative written for his sons. He was educated for four years at a school at Coxwold in Yorkshire, after which he was sent to Trinity College, Cambridge, graduating B.A. in 1651 and M.A. in 1655.
In 1658 he went to France with the Earl of Kildare, and on his return was present at the marriage of his second cousin Mary Fairfax to the Duke of Buckingham at Nun Appleton, Yorkshire. When Buckingham was sent to the Tower of London by the Protector, Brian accompanied his cousin Lord Fairfax to Whitehall when he went to demand his son-in-law's release. Brian was constantly with Lord Fairfax during the latter years of his life, and was present at his death. At the end of 1659 Lord Fairfax sent Brian Fairfax on a delicate and dangerous mission to General Monck, who was then in Scotland. In a tract named Iter Boreale, published in the "Fairfax Correspondence", Fairfax describes his journey and his interview with the general. On his return he found Lord Fairfax, 1 January 1660, calling to his standard the gentlemen of Yorkshire, and took an active part in their organisation. On 6 January he was despatched upon a mission from Lord Fairfax to Lenthall, the speaker of the House of Commons, in London, with an explanation of the intention of the movements in the north. Before his return Monck had reached Yorkshire, and Fairfax was present at the interview between Monck and Lord Fairfax at Nun Appleton.
Shortly afterwards, when the parliament sent a commission with Lord Fairfax at its head to the Hague to invite the return of Charles II, Brian Fairfaxaccompanied his cousin in the capacity of private secretary. He was afterwards associated with the Duke of Buckingham in two diplomatic visits to the continent, and also acted as Buckingham's agent until prudence led him to resign. He was appointed equerry to Charles II on 21 Jan. 1670, and held the office until the king's death, when he resigned. He took no part in politics under James II. In 1688 he went over to Holland with his young son Brian to pay his respects to the Princess Mary, who was godchild to his cousin the Duchess of Buckingham. He was received very cordially, and when William III came to the throne Brian was made one of his equerries. At the age of fifty-six he found the duties onerous, and after three years he accepted the post of secretary to a fellow-Yorkshireman, Archbishop Tillotson.