There have been seven baronetcies created for persons with the surname Sinclair, six in the Baronetage of Nova Scotia and one in the Baronetage of Great Britain. Four of the creations are extant as of 2008.
The Sinclair baronetcy, of Dunbeath in the County of Caithness, was created in the Baronetage of Nova Scotia on 3 January 1631 for John Sinclair. The title became extinct on his death in circa 1652.
The Sinclair baronetcy, of Canisbay in the County of Caithness, was created in the Baronetage of Nova Scotia on 2 June 1631 for James Sinclair, a great-grandson of the fourth Earl of Caithness. The seventh Baronet succeeded as twelfth Earl of Caithness in 1789. See this title for further history of the baronetcy.
The Sinclair, later Sinclair-Lockhart, baronetcy, of Murkle in the County of Caithness and of Stevenston in the County of Haddington, was created in the Baronetage of Nova Scotia on 18 June 1636. For more information on this creation, see Sinclair-Lockhart Baronets.
The Sinclair baronetcy, of Longformacus in the County of Berwick, was created in the Baronetage of Nova Scotia on 10 December 1664 for Robert Sinclair. The title became either extinct or dormant on the death of the seventh Baronet in circa 1843.
The Sinclair baronetcy, of Kinnaird in the County of Fife, was created in the Baronetage of Nova Scotia in circa 1675 for James Sinclair. Sir John Sinclair, 4th Baronet (born 1763) succeeded in the title in 1767 but nothing further is known about him or the baronetcy.
The Sinclair baronetcy, of Dunbeath in the County of Caithness, was created in the Baronetage of Nova Scotia on 12 October 1704 for James Sinclair, with remainder to his heirs male whatsoever. He was a descendant of George Sinclair, 4th Earl of Caithness. On the death of the fifth Baronet in 1842 the line of the first Baronet failed. The title was assumed by John Sinclair, of Barrock, great-great-grandson of George Sinclair of Barrock, brother of the first Baronet. The seventh Baronet was Vice-Lord-Lieutenant of Caithness. The eighth baronet was the father of politician Susan Cunliffe-Lister, Baroness Masham of Ilton. As of 2011 the eleventh and present Baronet, Jonathan Sinclair, is second in line of succession to the earldom of Caithness.
John Sinclair, 1st Baron Pentland, was the eldest son of Captain George Sinclair, youngest son of the sixth Baronet (see the Baron Pentland). Susan Cunliffe-Lister, Baroness Masham of Ilton, was the daughter of the eighth Baronet and the sister of the ninth Baronet.
The Sinclair baronetcy, of Ulbster in the County of Caithness, was created in the Baronetage of Great Britain on 14 February 1786. For more information on this creation, see the Viscount Thurso.
see the Earl of Caithness for further succession
Nothing further is known of this title
| Escutcheon: | Quarterlt 1st Azure a ship at anchor oars in saltire Or flagged Gules within a double tressure counterflory Or 2nd & 3rd Or a lion rampant Gules armed and langued Azure 4th Azure a ship under sail Or sails Argent and flags Gules over all dividing the four quarteres a cross engrailed Sable the whole within a bordure parted per pale the dexter side indented Gules the sinister Ermine. |
| Crest: | A cock Proper. |
| Motto: | Fidelitas (Fidelity)[2] |