The Town class was a group of twenty-one light cruisers built for the Royal Navy (RN) and Royal Australian Navy (RAN) of the first half of the 20th Century. These vessels were long-range cruisers, suitable for patrolling the vast expanse covered by the British Empire. These ships, initially rated as second class cruisers, were built to a series of designs, known as the Bristol, Weymouth, Chatham, Birmingham and Birkenhead classes – all having the names of British towns except for the RAN ships, which were named after Australian cities.

A light cruiser is a type of small or medium-sized warship. The term is a shortening of the phrase "light armored cruiser", describing a small ship that carried armor in the same way as an armored cruiser: a protective belt and deck. Prior to this smaller cruisers had been of the protected cruiser model, possessing armored decks only. While lighter and smaller than other contemporary ships they were still true cruisers, retaining the extended radius of action and self-sufficiency to act independently around the world. Cruisers mounting larger guns and heavier armor relative to most light cruisers would come to be known as heavy cruisers, though the designation of 'light' versus 'heavy' cruisers would vary somewhat between navies. Through their history light cruisers served in a variety of roles, primarily as convoy escorts and destroyer command ships, but also as scouts and fleet support vessels for battle fleets.