HMS Dorsetshire was a County-class heavy cruiser of the British Royal Navy, named after the English county, now usually known as Dorset. The ship was a member of the Norfolk sub-class, of which Norfolk was the only other unit; the County class comprised a further eleven ships in two other sub-classes. Dorsetshire was built at the Portsmouth Dockyard; her keel was laid in September 1927, she was launched in January 1929, and was completed in September 1930. Dorsetshire was armed with a main battery of eight 8 in (203 mm) guns, and had a top speed of 31.5 knots.

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".