The title Earl of Orkney has been created several times in the Peerage of Scotland. The first grant was to Henry Sinclair in 1379. His descendant, William Sinclair, surrendered the earldom of Orkney in exchange for the earldom of Caithness.

The next Orkney title was the dukedom of Orkney, which was given to James Hepburn, 4th Earl of Bothwell, husband of Queen Mary I, in 1567. Later that year, however, he forfeited the title when his wife was forced to abdicate.

The second creation of the title was for Lord Robert Stewart, an illegitimate son of King James V. His successor Patrick, however, forfeit the title.

The last creation of the earldom was in favour of the man who would become the first British Field Marshal, Lord George Hamilton, the fifth son of William Douglas, Duke of Hamilton. By marriage, the title passed to the O'Brien family, then to the Fitzmaurice family, and finally to the St John family. The present earl holds the subsidiary titles of Viscount of Kirkwall and Lord Dechmont. Both subsidiary titles were created at the same time as the earldom, in 1696.

Earls of Orkney, First Creation (1379)

• Henry Sinclair, 1st Earl of Orkney (d. 1400)
• Henry Sinclair, 2nd Earl of Orkney (d. 1418)
• William Sinclair, 3rd Earl of Orkney (d. 1480) (surrendered 1470)

Dukes of Orkney (1567)

• James Hepburn, 1st Duke of Orkney (c. 1535-1578) (forfeit 1567)

Earls of Orkney, Second Creation (1581)

• Robert Stewart, 1st Earl of Orkney (1533-1593)
• Patrick Stewart, 2nd Earl of Orkney (c. 1569-1614) (forfeit 1614)

Earls of Orkney, Third Creation (1696)

• George Hamilton, 1st Earl of Orkney (1666-1737)
• Anne O'Brien, 2nd Countess of Orkney (d. 1756)
• Mary O'Brien, 3rd Countess of Orkney (c. 1721-1791)
• Mary Fitzmaurice, 4th Countess of Orkney (1755-1831)
• Thomas John Hamilton Fitzmaurice, 5th Earl of Orkney (1803-1877)
• George William Hamilton Fitzmaurice, 6th Earl of Orkney (1827-1889)
• Edmond Walter Fitzmaurice, 7th Earl of Orkney (1867-1951)
• Cecil O'Bryen Fitzmaurice, 8th Earl of Orkney (1919-1998)
• Oliver Peter St John, 9th Earl of Orkney (b. 1938)

Heir Apparent: his son Oliver Robert St John, Viscount Kirkwall (b. 1969)