The men's single sculls event at the 2020 Summer Olympics took place from 23 to 30 July 2021 at the Sea Forest Waterway.

Of the 6 finalists from the 2016 Games, silver medalist Damir Martin of Croatia is the only one to return.

Two-time reigning gold medalist Mahé Drysdale was defeated by Jordan Parry in New Zealand's selection process.

[3] The three World Champions since the 2016 Games are Ondřej Synek of the Czech Republic (a three-time Olympic medalist), Kjetil Borch of Norway, and Oliver Zeidler of Germany.

Benin, the Dominican Republic, the Ivory Coast, Nicaragua, and Saudi Arabia made their debut in the event.

Italy and the Netherlands each made their 15th appearance, tied for most among nations competing in Tokyo and fourth-most among all nations (Great Britain at 22, the United States at 21, and Switzerland at 16 did not have competitors in this event at the 2020 Games).

Each National Olympic Committee (NOC) has been limited to a single boat (one rower) in the event since 1912.

The "scull" portion means that the rower uses two oars, one on each side of the boat; this contrasts with sweep rowing in which each rower has one oar and rows on only one side (not feasible for singles events).