HMS Alecto was an Alecto-class sloop designed by Sir William Symonds, Surveyor of the Navy.

She was broken up in November 1865 Alecto was the second named vessel since it was used for a 12-gun fireship, launched by King of Dover on 26 May 1781 and sold in 1802.

[Note 1] She was commissioned on 26 October 1839 under the command of Lieutenant William Hoseason, RN for service in the Mediterranean.

In March 1845 she participated in a series of trials with her near sister the screw-driven HMS Rattler.

[7] She commissioned on 10 November 1845 under the command of Lieutenant Francis William Austen, RN, for service on the east coast of South America.

[13] On 2 August 1855 she commissioned under Commander Robert Philips, RN, for the West Coast of Africa.

[18] She was commissioned on 27 January 1860 under Commander James Raby, RN, for continued service on the West Coast of Africa.

Her last commission was on 23 January 1863 under commander William Hans Blake, RN, for service on the east coast of South America.