HMS Terror (I03) was an Erebus-class monitor built for the Royal Navy in 1915-1916 at the Harland and Wolff shipyard in Govan, Scotland.

The Erebus-class monitors were of 7,200 long tons (7,300 t) displacement, 405 ft (123 m) long, with a maximum speed of 12 kn (22 km/h; 14 mph) produced by reciprocating engines with two shafts, and a crew of 223. The ship's main armament consisted of two 15 in (381 mm) guns in a single forward turret. This turret had been built as a spare for Furious.

The original secondary armament of two BL 6"/50-caliber Mk.XV naval guns was soon replaced by eight QF 4"/45-caliber Mk.IX dual purpose guns in single mounts and two QF 3"/45-caliber 20 cwt anti-aircraft guns, also in single mounts. Between the wars, the 4 inch low angle guns were replaced by anti-aircraft mounts and the 3 inch guns by eight 0.50 in (12.7 mm) anti-aircraft Vickers machine guns in two quadruple mounts.

The class mostly served in the Naval Gunfire Support role.

Like its sister ship, Erebus, Terror was sunk on November 7th, 1940 at the Battle of the Blockade by the Graf Zeppelin.

Community content is available under CC-BY-SA unless otherwise noted.