The Topcat is a one-design sailing catamaran boat class which is divided into several boat sizes.

The Topcat sailing catamarans are fast, seaworthy, popular, and affordable twin-hull boats ranging in size from 3.60 m (12 ft) to 5.50 m (18 ft). They have world-wide distribution and are differentiated by:

Production of the hulls in fiberglass
Hull design without daggerboards
Assembly without bolts
Transportable on a trailer (width less than 2.55 m to comply with German traffic laws)
Transportable on the roof rack of a car
Simplification of existing designs