Colin Duffy (born December 10, 2003) is an American professional rock climber who specializes in competition climbing.

At age 17, he became the youngest climber to qualify to compete at the 2020 Summer Olympic Games in Tokyo.

[5] At the 2020 Tokyo Olympics, he advanced to the final round of the sport climbing competition and finished in seventh place.

Two days later, Duffy won his second gold by finishing first in the men's competition lead climbing event.

He is the first male athlete to win both bouldering and lead climbing in the same IFSC World Cup event.