The schooner sail-plan has two or more masts with the forward mast being shorter or the same height as the rear masts. Most traditionally rigged schooners are gaff rigged, sometimes carrying a square topsail on the foremast and occasionally, in addition, a square fore-course (together with the gaff foresail). Schooners carrying square sails are called square-topsail schooners. Modern schooners may be Marconi or Bermuda rigged. In Bermuda, Bermuda rigged schooners had appeared by the early 19th Century. Known as Ballyhoo schooners, or, along with single masted relatives, with Bermuda or gaff rig, with or without a square topsail, as Bermuda sloops. A memorable example to the last type was HMS Pickle. Some schooner yachts are Bermuda rigged on the mainmast and gaff rigged on the foremast. A staysail schooner has no foresail, but instead carries a main staysail between the masts in addition to the fore staysail ahead of the foremast. A staysail or gaff topsail schooner may carry a fisherman (a four sided fore and aft sail) above the main staysail or foresail, or a triangular mule. Multi-masted staysail schooners usually carried a mule above each stay sail except the fore staysail. Gaff-rigged schooners generally carry a triangular fore-and-aft topsail above the gaff sail on the main topmast and sometimes also on the fore topmast (see illustration), called a gaff-topsail schooner. A gaff-rigged schooner that is not set up to carry one or more gaff topsails is sometimes termed a "bare-headed" or "bald-headed" schooner. A schooner with no bowsprit is known as a "knockabout" schooner.
The schooner may be distinguished from the ketch by the placement of the mainsail. On the ketch, the mainsail is flown from the most forward mast; thus it is the main-mast, and the other mast is the mizzen-mast. A two-masted schooner has the mainsail on the aft mast, and therefore the other mast is the fore-mast.
Schooners were more widely used in the United States than in any other country. Two masted schooners were and are most common. They were popular in trades that required speed and windward ability, such as slaving, privateering, blockade running and offshore fishing. They also came to be favoured as pilot vessels, both in the United States and in Northern Europe. In the Chesapeake Bay area several distinctive schooner types evolved, including the Baltimore clipper and the pungy.
There was no set maximum number of masts for a schooner. A small schooner has two or three masts, but they were built with as many as six (e.g. the wooden six-masted Wyoming) or seven masts to carry a larger volume of cargo. The only seven-masted (steel hulled) schooner, the Thomas W. Lawson, was built in 1902, with a length of 395 ft (120 m), the top of the tallest mast being 155 feet above deck, and carrying 25 sails with 43,000 ft² (4,000 m²) of total sail area. A two or three masted schooner is quite maneuverable and can be sailed by a smaller crew than some other sailing vessels. The larger multi-masted schooners were somewhat unmanageable and the rig was largely a cost-cutting measure introduced towards the end of the days of sail.