HMS Severn was an Endymion-class frigate of the British Royal Navy, launched in 1813 as one of five heavy frigates built to match the powerful American frigates. The shortage of oak meant that she was built of "fir" (actually pine), which meant a considerably shortened lifespan. Nonetheless, the ship saw useful service, especially at the bombardment of Algiers in 1816, before being broken up in 1825.

Severn was ordered as a Leda-class frigate of 38 guns, and was to have borne the name Tagus. Relative to her prototype, she received two more guns forward. Tagus was renamed Severn on 7 January 1813, i.e., well before her launching.

Initially commissioned under the command of Captain Joseph Nourse, Severn served in the North Atlantic. On 18 January 1814 she was escorting a convoy from England to Bermuda when she encountered the French 40-gun frigates Sultane and Étoile. Severn drew them away from the convoy, saving it. After a long chase, the French frigates gave up and sailed away.

Later the same year, on 1 May, she captured the American privateer schooner Yankee Lass, armed with nine guns and carrying a crew of 80 men. She was 20 days out of Rhode Island and had not made any captures. At the time, Severn was in company with Surprise.

Severn was among the several British warships that shared in the proceeds of the capture on 10 July of the American schooners William, Eliza, Union, and Emmeline, and the capture on 2 July of the schooner Little Tom.

In the late summer and autumn of 1814, Severn was an important participant in the War of 1812, as she was stationed in Chesapeake Bay to blockade the Patuxent River. It was from this point that the British launched their invasion of Maryland, which led to the Battle of Bladensburg and then the subsequent burning of Washington D.C. On 2 July Severn and Loire captured two schooners, two gun-boats, and a sloop. They also destroyed a large store of tobacco.

On 20 August Severn, the frigate Hebrus, and the gun-brig Manly sailed up the Patuxent to follow the boats as far as possible. Admiral Alexander Cochrane and his force of marines and seamen entered Washington on the night of 24 August. The British then burnt the White House, the Treasury, and the War Office. They left at 9 o'clock on the evening of the next day and returned to Nottingham, Maryland, on the Patuxent where Cochrane boarded Manly. The campaign cost the Navy one man killed and six wounded, including one man of the Corps of Colonial Marines killed and three wounded.

The draught of this class of frigate was too deep to permit Severn and her sister ships from sailing into the harbour at Baltimore. Her sailors had to kedge rafts holding small cannon and rocket launchers seven miles up the river to Fort McHenry. During the attack on Baltimore Admiral Sir George Cockburn raised his flag on Severn. Although the navy contributed seamen and marines to the land attack, and took casualties, Severn did not suffer any losses.