Mercedes-Benz introduced a Roadster version of the 300SL at the 1957 Geneva Motor Show. Like the Gullwing, the Roadster featured roughly the same engineering underneath, but the body was changed to incorporate regular doors.

Detail differences included larger front fenders, larger 'euro' headlights, a smaller grille, a rounder front windscreen and a chrome accent strip running down the side of the car. The Roadster is slightly heavier than its coupe counterpart.

The rear suspension was also revised with a single-point swing axle and an additional coil spring. The engine was only slightly updated to include a sports camshaft and a higher 9.5:1 compression ratio. This helped the car achieve a top speed near 155 mph.