The men's marathon event at the 2020 Summer Olympics is scheduled to take place on 8 August 2021 in Sapporo. Approximately eighty athletes were initially expected to compete (target number of 80) by entry time or ranking; the final number is of 110 runners qualified by time, with NOCs universality places yet to enter athletes in addition to the 110 qualifying through time, much more than the expected due to the postponed Games (4 universality places were used in 2016). The qualification period for "Entry Standard" (2:11:30) was from 1 January 2019 to 31 May 2021, with a maximum quota per NOC of 3.Performances achieved between 6 April 2020 and 30 November 2020 were not considered in the qualification system. The defending champion is Kenyan Eliud Kipchoge.