The men's 110 metres hurdles event was part of the track and field athletics programme at the 1920 Summer Olympics.

Thomson, who had lived in the United States since age 8, had wanted to run for the U.S. team but was ineligible due to his Canadian citizenship.

The United States made its sixth appearance, the only nation to have competed in the 110 metres hurdles in each Games to that point.

The competition used the three-round basic format introduced in 1908, though the effectiveness of the first round in narrowing the field was dramatically increased compared to 1908 and 1912.

In the semifinals, Harold Barron and Earl Thomson equalled the world record with 15.0 seconds.