| OBC Mantorp | |
| Oettinger Golf 500R | custom-builds, hatchbacks, Volkswagen |
| Ogle Design SX1000 1962-1964 | kit-car, Ogle |
| Ogle Design SX250 1962 | concepts-prototypes, coupes, Ogle |
| Oil Stain Lab Porsche Half11 2023-current (HF-11) | coupes, custom-builds, open-top-cars, Porsche, supercars |