HMS Trenchant was a modified Admiralty R-class destroyer which served with the Royal Navy.

Trenchant was one of ten Modified R-class destroyers ordered by the British Admiralty in March 1916 as part of the Eighth War Construction Programme.

A total of 296 long tons (301 t) of fuel oil was carried, giving a design range of 3,450 nautical miles (6,390 km; 3,970 mi) at 15 knots (28 km/h; 17 mph).

[5] Armament consisted of three QF 4in Mk IV guns on the ship's centreline, with one on the forecastle, one on a raised platform aft and one between the funnels.

[4] Trenchant was laid down by J. Samuel White at East Cowes on the Isle of Wight with the yard number 1481, and launched on 28 June the following year.

[16] While undergoing a refit in Haulbowline on 3 June 1921, Trenchant was attacked by Republican forces during the Irish War of Independence but suffered little damage.