HMS Caroline is a decommissioned C-class light cruiser of the Royal Navy that saw combat service in the First World War and served as an administrative centre in the Second World War. Caroline was launched and commissioned in 1914. At the time of her decommissioning in 2011 she was the second-oldest ship in Royal Navy service, after HMS Victory. She served as a static headquarters and training ship for the Royal Naval Reserve, based in Alexandra Dock, Belfast, Northern Ireland, for the later stages of her career. She was converted into a museum ship. From October 2016 she underwent inspection and repairs to her hull at Harland and Wolff and opened to the public on 1 July 2017 at Alexandra Dock in the Titanic Quarter in Belfast.

The C class was a group of twenty-eight light cruisers of the Royal Navy, and were built in a sequence of seven groups known as the Caroline class, the Calliope class, the Cambrian class, the Centaur class, the Caledon class, the Ceres class and the Carlisle class. They were built for the rough conditions of the North Sea, and proved to be rugged and capable vessels, despite being somewhat small and cramped.