HMS Inconstant was a 36-gun Perseverance-class fifth-rate frigate of the Royal Navy. She had a successful career serving in the French Revolutionary and Napoleonic Wars, capturing three French warships during the French Revolutionary naval campaigns, Curieux, Unité, and the former British ship HMS Speedy.

The Perseverance-class frigate was a 36-gun, later 42-gun, 18-pounder fifth-rate frigate class of twelve ships of the Royal Navy, constructed in two batches. Designed by Surveyor of the Navy Sir Edward Hunt the first iteration, consisting of four ships, was constructed as a rival to the similar Flora-class frigate. Strongly built ships, the Perseverance class provided favourable gunnery characteristics and was highly manoeuvrable, but bought these traits with a loss of speed. The name ship of the class, Perseverance, was ordered in 1779 and participated in the American Revolutionary War, but her three sister ships were constructed too late to take part. The class continued in service after the war, but soon became outdated.