J-Boats are an American boat builder based in Newport, Rhode Island and founded by Rod Johnstone in 1977. The company specializes in the design and manufacture of fiberglass sailboats.

The company's boat model designations all start with "J/" and then the design's length overall, usually in feet or, more recently, in decimeters. All J/Boat designs are monohull, sloop-rigged keelboats constructed of fiberglass. The current company product line consists of ten models ranging in length from 22.75 to 40 ft (6.9 to 12.2 m).[4] Past models have ranged from 22.5 to 64.5 ft (6.9 to 19.7 m), from the J/22 to the J/65.