Alexander Gordon, 4th Duke of Gordon, KT (18 June 1743 – 17 June 1827), styled Marquess of Huntly until 1752, was a British Army officer who was described by Lord Kames as the "greatest subject in Britain". He was also known as the "Cock o' the North", the traditional epithet of the chief of Clan Gordon.

Alexander Gordon was born at Gordon Castle, Fochabers, on 18 June 1743, the eldest son of Cosmo Gordon, 3rd Duke of Gordon, and his wife, Lady Catherine Gordon, daughter of the 2nd Earl of Aberdeen. He was educated at Eton and also possibly at Harrow. He succeeded as 4th Duke of Gordon in 1752. His younger brother was Lord George Gordon, who incited the Gordon riots.

He was elected as a Scottish representative peer in 1767. In 1778 the government allocated funds to raise three fencible regiments in 'North Britain', one of which was the 'Gordon Fencibles' or North Fencibles' raised by Gordon for the Anglo-French War 1778-83, this was disbanded in 1783. He was appointed a Knight of the Thistle in 1775 and was created a Peer of Great Britain as Baron Gordon of Huntley, of Huntley in the County of Gloucester, and Earl of Norwich, in the County of Norfolk, in 1784. His new titles were not universally popular. He was thought to have taken designations to which he had no right. The Scots Peerage described the Gordon of Huntley peerage as "an absurd specimen of Peerage topography. The village of Huntley, four miles from Newent in Gloucestershire, had apparently no connection with the Gordon family or with the town of Huntly in North Britain." George Edward Cokayne in The Complete Peerage says the following with regard to the Duke's choice of Norwich for his earldom: "His great-grandmother was the daughter of the 5th Duke of Norfolk and 1st Earl of Norwich, but though that title had become extinct in 1777, the representation thereof did not vest in the issue of that lady."

He was Keeper of the Great Seal of Scotland from 1794 to 1806 and from 1807 to 1827. Between 1793 and 1827, he was Chancellor of King's College, Aberdeen. In addition, he was Lord Lieutenant of Aberdeenshire until 1808. He received the Order of the Thistle from King George III on 11 January 1775. The Dictionary of National Biography described him thus: "At the time of his marriage the Duke was reputed one of the handsomest men of his day".

He raised the 92nd (Gordon Highlanders) Regiment of Foot in 1794 for the French Revolutionary Wars. He was responsible for establishing the new village of Fochabers as well as those of Tomintoul and Portgordon in Banffshire. He is also credited as the founder of the Gordon Setter breed of dog, having popularised a 200-year-old breed during the 18th century and then formalised its breed standard in 1820.

He was an enthusiastic supporter and patron of the music of William Marshall (1748–1833), a Scottish fiddler and composer, and famous for his many strathspeys, who acted as steward of the Gordon household.

The 4th Duke of Gordon took a paternalistic view of his tenants, seeing his estates as a breeding ground for recruits to the army. He was therefore opposed to depopulating the Highlands and averse to removing tenants even when they were unable to pay their rents. However, with his own debts mounting, the Glen Feshie estate was sold to George Macpherson Grant of Ballindalloch in 1815. Glenbanchor was sold to James Macpherson of Belleville in 1822, the money raised going to fund improvements at Huntly.

Gordon married firstly on 23 October 1767 at Ayton, Scottish Borders, and again at Mr. Fordyce's house in Argyll Street, Edinburgh, Jane, the daughter of the late Sir William Maxwell, 3rd Baronet of Monreith, by his wife, the Lady Magdalen Maxwell, daughter of William Blair, of Blair, Ayrshire. Jane was described by the diarist Sir Nathaniel Wraxall as a celebrated beauty. From 1787 she was part of the social centre of the Tory party and was described in the Female Jockey Club of 1794 as possessing "an open ruddy countenance, quick in repartée, and no one excelling her in performing the honours of the table, her society is generally courted". It went on to say that