The men's decathlon event at the 2020 Summer Olympics took place on 4 and 5 August 2021 at the Japan National Stadium.

Due to the COVID-19 pandemic, the period was suspended from 6 April 2020 to 30 November 2020, with the end date extended to 29 June 2021.

The qualifying time standards could be obtained in various meets during the given period that have the approval of the IAAF.

Prior to this competition, the existing world, Olympic, and area records were as follows.

[1] 1 Van Der Plaetsen was forced to retire from the competition after pulling his achillies tendon during his second attempt in the long jump.