The Castle-class corvette was an ocean going convoy escort developed by the United Kingdom during the Second World War. It was the follow-on to the Flower-class corvette, and designed to be built in shipyards that were producing the Flowers. The Castle-class was a general improvement over the smaller Flowers which were designed for coastal rather than open ocean use.

The Castle-class corvettes started appearing in service during late 1943.

96 Castles were ordered from yards in the UK and Canada. Fifteen British and all 37 Canadian ships were later cancelled; Canada receiving twelve British-built ships instead. The UK completed a further five as convoy rescue ships for the Merchant Navy. Four became weather ships after the war.

The Castle resembled later Flowers with an extended forecastle and mast behind the bridge, but was 420 tons heavier and 37 feet longer. The Admiralty Experiment Works at Haslar developed an improved hull form which, in combination with the increased length, made the Castle at least half a knot faster than the Flower despite using the same engine. The Castle also had a single-screw. A lattice mainmast was used instead of the pole version fitted to the Flowers. The Castles were fitted with Squid anti-submarine mortars whereas the Flowers used Hedgehog mortars.

Source: Ships