HMS Relentless was an R-class destroyer of the Royal Navy that saw service during World War II.

Commissioned at Greenock on 30 November 1942, Relentless performed anti-submarine escort duties and patrolling activities in the South Atlantic and Indian Ocean for the balance of the war.

[4] In 1953 she took part in the Fleet Review to celebrate the Coronation of Queen Elizabeth II.

On 27 June 1964 she was re-commissioned to serve as part of the 29th Escort Squadron, to replace the destroyer Diana.

The Commanding Officer from 1951 to 1952 was Captain Michael Le Fanu RN.