HMS Mullett (or Mullet) was a Royal Navy 5-gun Philomel-class wooden screw gunvessel launched in 1860.

The Admiralty ordered a further twelve of the class on 14 June 1859 with this new classification, including the Mullett, and they received their names on 24 September.

She was fitted with a Robert Napier & Sons two-cylinder horizontal single-expansion steam engine driving a single screw and developing 355 indicated horsepower (265 kW).

[2] On 28 June 1866, Mullett, under Captain Robinson, and in company with the small colonial steamer Dover, landed a force of about 400 British troops under Colonel D'Arcy, primarily from the West India Regiment, at Bathurst in the Gambia.

The force, joined by local allies, stormed a Marabout stronghold after Mullett had ineffectively shelled the stockade with her 68-pounder for four hours.

In 1869, while the ship was in Jamaica, Able Seaman William Wardell won a Royal Humane Society Bronze Medal for saving the life on 10 June of Robert Cleal, an armourer of Terror.

Then during the Russian war scare in the late 1880s, the government of Victoria bought several old vessels, including Formosa as blockships for the south and west channels.