Athletics at the 2020 Summer Olympics – Mixed 4 × 400 metres relay

This was the first appearance of the event, added along with mixed team events in multiple sports for the 2020 Games. The mixed relay was first introduced at the 2017 IAAF World Relays. It was added to the World Championship programme at the 2019 World Athletics Championships. The event used the two-round format introduced for other relay events in 2012. Each team consists of two men and two women. The team members can run in any order. Prior to this competition, the existing world, Olympic, and area records are as follows. ==Qualification==

A National Olympic Committee (NOC) could qualify a relay team of 4 athletes in one of three ways. A total of 16 NOCs qualified. • The top 8 NOCs at the 2019 World Athletics Championships qualified a relay team. • The top 8 NOCs at the 2021 World Athletics Relays qualified a relay team. • Where an NOC placed in the top 8 at both the 2019 World Championships and the 2021 World Relays, the quota place was allocated to the world ranking list as of 29 June 2021. In this case, 3 teams did so, so there are 3 places available through the world rankings. The qualifying period was originally from 1 May 2019 to 29 June 2020. 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. Both indoor and outdoor meets are eligible. The most recent Area Championships may be counted in the ranking, even if not during the qualifying period. ==Results==

Round 1 The two heats of round 1 were held on 30 July 2021 and started at 20:00 (UTC+9). Final The final was held on Saturday, 31 July 2021 at 21:35 (UTC+9). ==Notes==