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. The seventh Baronet succeeded as twelfth Earl of Caithness

Earl of Caithness

Earl of Caithness is a title that has been created several times in the Peerage of Scotland, and has a very complex history. Its first grant, in the modern sense as to have been counted in strict lists of peerages, is now generally held to have taken place in favor of Maol Íosa V, Earl of...

 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 Stevenson 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

Sinclair-Lockhart Baronets

The Sinclair, later Sinclair-Lockhart Baronetcy, of Murkle in the County of Caithness and of Stevenson in the County of Haddington, is a title in the Baronetage of Nova Scotia. It was created on 18 June 1636 for John Sinclair, with remainder to his heirs male whatsoever. The third Baronet was a...

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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 (b. 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. As of 2011 the eleventh and present Baronet is second in line of succession to the earldom of Caithness.

John Sinclair, 1st Baron Pentland

John Sinclair, 1st Baron Pentland

John Sinclair, 1st Baron Pentland, GCSI, GCIE was a Scottish Liberal Party politician, soldier, peer, administrator and Privy Councillor who served as the Secretary of Scotland from 1905 to 1912 and the Governor of Madras from 1912 to 1919.Baron Pentland was born John Sinclair to Sir John...

, was the eldest son of Captain George Sinclair, youngest son of the sixth Baronet (see the Baron Pentland

Baron Pentland

Baron Pentland, of Lyth in the County of Caithness, was title in the Peerage of the United Kingdom. It was created in 1909 for the Scottish Liberal politician John Sinclair. He later served as Governor of Madras...

). Susan Cunliffe-Lister, Baroness Masham of Ilton

Susan Cunliffe-Lister, Baroness Masham of Ilton

Susan Cunliffe-Lister, Dowager Countess of Swinton, DSG, DL, Baroness Masham of Ilton in her own right is a crossbench member of the House of Lords. She is the senior female life peer....

, is 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

Viscount Thurso

Viscount Thurso, of Ulbster in the County of Caithness, is a title in the Peerage of the United Kingdom. It was created in 1952 for the Scottish Liberal politician and former Secretary of State for Air, Sir Archibald Sinclair, 4th Baronet. His son, the second Viscount, served as Lord Lieutenant of...

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Sinclair Baronets, of Canisbay (1631)

• Sir James Sinclair, 1st Baronet (d. 1662)
• Sir William Sinclair, 2nd Baronet (d. c. 1677)
• Sir James Sinclair, 3rd Baronet (d. c. 1710)
• Sir James Sinclair, 4th Baronet (d. c. 1730)
• Sir James Sinclair, 5th Baronet (d. 1760)
• Sir John Sinclair, 6th Baronet (d. 1774)
• Sir James Sinclair, 7th Baronet (1766-1823) (succeeded as Earl of Caithness in 1789)

see the Earl of Caithness

Earl of Caithness

Earl of Caithness is a title that has been created several times in the Peerage of Scotland, and has a very complex history. Its first grant, in the modern sense as to have been counted in strict lists of peerages, is now generally held to have taken place in favor of Maol Íosa V, Earl of...

 for further succession

Sinclair, later Sinclair-Lockhart Baronets, of Murkle and Stevenson (1636)

• see Sinclair-Lockhart Baronets
  Sinclair-Lockhart Baronets
  The Sinclair, later Sinclair-Lockhart Baronetcy, of Murkle in the County of Caithness and of Stevenson in the County of Haddington, is a title in the Baronetage of Nova Scotia. It was created on 18 June 1636 for John Sinclair, with remainder to his heirs male whatsoever. The third Baronet was a...
  
  

Sinclair Baronets, of Longformacus (1664)

• Sir Robert Sinclair, 1st Baronet (d. 1678
• Sir John Sinclair, 2nd Baronet (d. after 1696)
• Sir Robert Sinclair, 3rd Baronet (d. 1727)
• Sir John Sinclair, 4th Baronet (d. 1764)
• Sir Harry Sinclair, 5th Baronet (d. 1768)
• Sir John Sinclair, 6th Baronet (d. 1798)
• Sir John Sinclair, 7th Baronet (d. c. 1843)

Sinclair Baronets, of Kinnaird (c. 1675)

• Sir James Sinclair, 1st Baronet (d. c. 1702
• Sir George Sinclair, 2nd Baronet (d. 1726)
• Sir John Sinclair, 3rd Baronet (d. 1767)
• Sir John Sinclair, 4th Baronet (b. 1763)

Nothing further is known of this title

Sinclair Baronets, of Dunbeath (1704)

• Sir James Sinclair, 1st Baronet (d. 1742)
• Sir William Sinclair, 2nd Baronet (d. 1767)
• Sir Alexander Sinclair, 3rd Baronet (d. 1786)
• Sir Benjamin Sinclair, 4th Baronet (d. 1796)
• Sir John Sinclair, 5th Baronet (d. 1842)
• Sir John Sinclair, 6th Baronet (1794-1873)
• Sir John Rose George Sinclair, 7th Baronet (1864-1926)
• Sir Ronald Norman John Charles Udny Sinclair, 8th Baronet (1899-1952)
• Sir John Rollo Norman Blair Sinclair, 9th Baronet (1928-1990)
• Sir Patrick Robert Richard Sinclair, 10th Baronet (1936-2011)
• Sir William Sinclair, 11th Baronet