A flotilla (from Spanish, meaning a small flota (fleet) of ships, and this from French flotte), or naval flotilla, is a formation of small warships that may be part of a larger fleet. A flotilla is usually composed of a homogeneous group of the same class of warship, such as frigates, destroyers, torpedo boats, submarines, gunboats, or minesweepers. Groups of larger warships are usually called squadrons, but similar units of non-capital ships may be called squadrons in some places and times, and flotillas in others.
A flotilla is usually commanded by a Rear Admiral, a Commodore or a Captain, depending on the importance of the command (a Vice Admiral would normally command a squadron). A flotilla is often divided into two or more divisions, each of which might be commanded by the most senior Commander. A flotilla is often, but not necessarily, a permanent formation.
In modern navies, flotillas have tended to become administrative units containing several squadrons. As warships have grown larger, the term squadron has gradually replaced the term flotilla for formations of destroyers, frigates and submarines in many navies.
A naval flotilla has no direct equivalent on land, but is, perhaps, the rough equivalent in value of a brigade or regiment.