The Sunfish is a personal-size, beach-launched sailing dinghy. It features a very flat, boardlike hull carrying an Oceanic lateen sail mounted to an un-stayed mast.

Sunfish was developed by Alcort, Inc. and first appeared around 1952 as the "next generation" improvement on their original boat, the Sailfish. In contrast, the Sunfish has a wider beam for more stability, increased freeboard and the addition of a foot-well for a more comfortable sailing position. Sunfish began as a wood hull design and progressed to fiberglass construction just a few years after its introduction.

Having a Lateen sail with its simple two line rigging makes a Sunfish simple to learn sailing on and to set up. Upgrades can be added to enhance sail control for competitive sailing, making the boat attractive to both novice and experienced sailors alike.

Due to the broad appeal of the Sunfish, in 1995 it was commended by The American Sailboat Hall of Fame for being "the most popular fiberglass boat ever designed, with a quarter million sold worldwide" (at that point in time).

Early in 2016, manufacturer Laser Performance moved production from Portsmouth, Rhode Island, US to China and boats were supplied to the 2016 World Championships.

In 2017, Laser Performance (LP) announced the creation of a new governing body to manage the Sunfish Class, the International Sunfish Class Organization (ISCO), after the International Sunfish Class Association (ISCA), governing body since 1969, refused to sign a trademark agreement. In response the ISCA, still the World Sailing recognised Class Association, have announced rule changes which permit alternative suppliers to Laser Performance for some components.

Today, the Sunfish brand-name has become so widely known it is often misapplied generically to refer to any brand of board-style boat sporting the characteristic crab claw sail. The design is currently manufactured by Laser Performance.