The men's omnium event at the 2020 Summer Olympics took place on 5 August 2021 at the Izu Velodrome.

The previous reigning Olympic champion was Elia Viviani of Italy.

France, Italy, Russia, Germany, China, Great Britain, Australia, and the Netherlands are traditionally strong track cycling nations.

[3] A National Olympic Committee (NOC) could enter up to 1 cyclist in the omnium.

The format has changed significantly from 2016, with three of the six race types dropped and one replacement added.