HMS Dictator was a 64-gun third-rate ship of the line of the Royal Navy, launched on 6 January 1783 at Limehouse. She was converted into a troopship in 1798, and broken up in 1817.
At the "Reduction of Trinidad" in 1797 Dictator participated in the later stages, not having arrived until 18 February, the prize money awarded reflecting this late arrival.
On 8 March 1801, whilst disembarking the army at the Battle of Aboukir during the French campaign in Egypt, one seaman was killed and a midshipman, Edward Robinson, fatally wounded.
Prize money for the capture of enemy ships was usually shared with other warships in the squadron between 1801 and 1806.
Because Dictator served in the navy's Egyptian campaign between 8 March 1801 and 2 September, her officers and crew qualified for the clasp "Egypt" to the Naval General Service Medal that the Admiralty issued in 1847 to all surviving claimants.
In the late summer of 1807, Dictator was part of Admiral Gambier's fleet in the Øresund at the Battle of Copenhagen where she shared prize money with some 126 other British naval ships. She was again in Danish Waters the following year, in Admiral Hood's squadron of four ships-of-the-line together with some smaller vessels, tasked with maintaining the blockade between Jutland and Zealand. Her captain, Donald Campbell, ordered the sloop HMS Falcon to proceed on her successful patrols to Samsø, Tunø and Endelave.
In August 1809 Dictator was tasked with the occupation of the Pea Islands to the east of Bornholm but ran aground en route and had to be towed back to Karlskrona for repairs.
In early July 1810, during the Gunboat War with Denmark-Norway, Dictator, in company with Edgar and Alonzo, sighted three Danish gunboats commanded by Lieutenant Peter Nicolay Skibsted, who had captured Grinder in April of that year. The gunboats (Husaren, Løberen, and Flink) sought refuge in Grenå, on eastern Jutland, where a company of soldiers and their field guns could provide cover. However, the British mounted a cutting out expedition of some 200 men in ten ships’ boats after midnight on 7 July, capturing the three gunboats.
In 1812 Dictator led a small squadron consisting of three brigs, the 18-gun Cruizer-class brig-sloop Calypso, 14-gun brig-sloop Podargus and the 14-gun gun brig Flamer. On 7 July they encountered the Danish-Norwegian vessels Najaden, a frigate finished in 1811 in part with parts salvaged from a ship-of-the-line destroyed in earlier battles, and three brigs, Kiel, Lolland and Samsøe. Najaden was under the command of Danish naval officer Hans Peter Holm (1772–1812) In the subsequent Battle of Lyngør Dictator destroyed Najaden and the British took Laaland and Kiel as prizes but had to abandon them after the two vessels grounded. The action cost Dictator five killed and 24 wounded. In 1847 the surviving British participants were authorized to apply for the clasp "Off Mardoe 6 July 1812" to the Naval General Service Medal.
HMS Dictator was among Admiral Alexander Cochrane's fleet moored off New Orleans at the start of 1815.