János Zemen is a Hungarian Olympic middle-distance runner.

He represented his country in the men's 1500 meters at the 1976 Summer Olympics.

His time was a 3:44.27 in the first heat, a 3:39.94 in the semifinals, and a 3:43.02 in the finals.

He also competed in the men's 800 metres, posting a time of 1:47.40 in the heats.

This biographical article relating to Hungarian athletics is a stub.