A roadster is a two-seat, open car, traditionally without side windows (possibly with pluggable doortops), so that even with the lightweight convertible top raised the driver and passenger remain exposed to the elements. In modern times, the word is often used to describe a two-seat convertible without fixed window frames, especially a light-weight sportscar. Here, the use of the name 'roadster' is more a marketing than a technical one, invoking the feeling of an open-top machine for enjoyment, like those of the past.

Traditionally, roadster bodies were used on anything from a Ford Model T to a Cadillac V-16. It was a body style favored by those who preferred enjoyment to practicality. Roadster-bodied cars are popular with collectors, and are often valued higher than even other open styles.

The roadster name experienced a resurgence in 1990 with the introduction of the Mazda MX_5/Miata. Though not roadsters in the traditional open sense, many manufacturers today offer "roadsters". Notable vehicles include the BMW Z4, Honda S2000, Mercedes SLK, Porsche Boxster, Toyota MR-Spyder and the Fiat barchetta.

Italian makers favor the term Barchetta for a completely open-topped vehicle.

Also see: hot rod, convertible, spyder, cabriolet, drophead