HMS Norfolk was a County-class heavy cruiser of the Royal Navy; along with her sister ship Dorsetshire she was part of a planned four-ship subclass. She served throughout the Second World War, where she was involved in the sinking of the German Navy's battleships Bismarck and Scharnhorst.

The County class was a class of heavy cruisers built for the Royal Navy in the years between the First and Second World Wars. They were the first post-war cruisers constructed for the Royal Navy and were designed within the limits of the Washington Naval Treaty of 1922. Such ships, with a limit of 10,000 tons standard displacement and 8-inch calibre main guns may be referred to as "treaty cruisers".