| Birth Date: | 1962 12, df=yes |
| Birth Place: | Bento Gonçalves, Brazil |
| Height: | 1.95 m |
| Weight: | 87 kg |
| Position: | Outside hitter |
| Teamnumber: | 9 |
| Nationalyears: | 1983–1984 |
| Show-Medals: | yes |
Marcus Vinícius Simões Freire (born 6 December 1962) is a Brazilian sports official and retired volleyball player. He won a gold medal at the 1983 Pan American Games and a silver at the 1984 Olympics. After retiring from competitions he became a sports functionary. He is the current Executive Director of the Brazilian Olympic Committee and a Chef de Mission of the Brazilian team at the 2016 Summer Olympics.