| Marius Theiler | |
| Nationality: | Swiss |
| Sport: | Sprinting |
| Event: | 4 × 400 metres relay |
| Birth Date: | 23 August 1938 |
Marius Theiler (born 23 August 1938) is a Swiss sprinter. He won bronze in the men's 4 × 400 metres relay event at the 1962 European Athletics Championships.[1] Two years later, he competed in the men's 4 × 400 metres relay at the 1964 Summer Olympics.[2]