Marian Simion (born September 14, 1975) is a Romanian boxer, who competed in the Light Middleweight (71 kg) at the 1996 Summer Olympic as a Welterweight, winning a bronze medal and at the 2000 Summer Olympics where he won the silver medal. He repeated that feat one year later, at the 2001 World Amateur Boxing Championships in Belfast after having won the world title at the previous tournament in Houston, Texas.
He is the older brother of Olympian Dorel Simion.
- Defeated Hussein Bayram (France) 13-6
- Defeated Fernando Vargas (United States) 8-7
- Defeated Hasan Al (Denmark) 16-8
- Lost to Juan Hernández Sierra (Cuba) 7-20