A yawl is a two-masted sailing craft whose mizzen, or aft-most mast, is usually substantially shorter than the mainmast and is positioned aft of the rudderstock. The word yawl was first recorded in the 1600s and derives from the Dutch jol. Historically the term was also used for a ship's boat with oars.
A yawl is similar to a ketch; whereas the mizzen mast is forward of the rudder stock in the case of a ketch, it is aft of this point in the yawl rig. Additionally, the mizzen sail tends to be significantly smaller relative to the mainsail for the yawl compared to the ketch.  about one quarter the size of the mainsail, compared to the mizzen sail of a ketch, which may be about half the size of the mainsail. A boat with a mizzen sail sized between that of the ketch and the yawl was called a dandy, although this term has fallen out of use. An advantage of the yawl's aft-positioned mizzen mast is that its boom does not swing across the deck.
The yawl was originally developed for fishing boats, for example the Salcombe Yawl. While the classic looks of the rig is considered attractive, it is less efficient than a ketch, and is rarely seen on modern yachts.
Yawls were built for yacht racing in the 1950s and 1960s because of a handicapping loophole where boats were not penalized for having a mizzen sail. The design became popular with single-handed circumnavigators like Francis Chichester and Joshua Slocum because the sail-plan was advantageous sailing downwind and helped keep the boat on course, although the latter function is today better performed by modern autopilot systems.