| Event: | Men's 4 × 100 metres relay |
| Competition: | 2021 World Athletics Relays |
| Venue: | Silesian Stadium, Chorzów |
| Dates: | 1 May (heats) & 2 May (final) |
| Nations: | 18 |
| Win Value: | 39.21 |
| Gold: | Fausto Desalu Marcell Jacobs Davide Manenti Filippo Tortu |
| Goldnoc: | ITA |
| Silver: | Ryuichiro Sakai Hiroki Yanagita |
| Silvernoc: | JPN |
| Bronze: | Simon Hansen Tazana Kamanga-Dyrbak Kojo Musah Frederik Schou-Nielsen |
| Bronzenoc: | DEN |
| Prev: | 2019 |
| Next: | 2024 |
The men's 4 × 100 metres relay at the 2021 World Athletics Relays has been held at the Silesian Stadium on 1 and 2 May.
Only 18 teams participated of 24 possible qualifiers, with the USA (CR), Jamaica (WR), Canada, Great Britain, Trinidad and Tobago, and China (WL) not entering.On the 19 teams qualified by entry standard (38.80), Thailand and Chinese Taipei also declined to participate, same as Australia, first of the following top list. The 10 best placed teams will qualify for the 2022 World Championships in Eugene.
5 nations which made the men’s 4x100m final at the 2019 IAAF World Athletics Championships in Doha are entered – Brazil, France, Japan, the Netherlands and South Africa – their qualification for Tokyo is also already secured.[1] The 8 finalist teams will join them if different ones.
Prior to the competition, the records were as follows:
| World record |  Jamaica(Nesta Carter, Michael Frater, Yohan Blake, Usain Bolt) | 36.84 |  London, Great Britain | 11 August 2012 | |
| Championships record |  United States(Mike Rodgers, Justin Gatlin, Tyson Gay, Ryan Bailey) | 37.38 | Nassau, Bahamas | 2 May 2015 | |
| World Leading |  China (Su Bingtian, Xie Zhenye, Wu Zhiqiang, Wang Zhihong) | 38.29 | Shenzhen, China | 20 March 2021 |
According to World Athletics,[2] there were 2 teams who were possible favorite winners:
There are 6 possible runners-up for the final:
6 more teams to complete the 10 World Championships qualifiers:
| KEY: | bgcolor=ccffcc align=center | Q | Qualified | bgcolor=ddffdd align=center | q | Qualified as fastest times | WL | World leading | NR | National record | SB | Seasonal best | OG | 2020 Olympic Games qualification | WC | 2022 World Championships qualification |
Heats Qualification: First 2 of each heat (Q) plus the 2 fastest times (q) advanced to the final.[3]
| Rank | Heat | Nation | Athletes | Time | Notes |
|---|---|---|---|---|---|
| 1 | 3 | 38.45 | Q, EL, *OG, *WC | ||
| 2 | 2 | 38.45 | Q, SB, *WC | ||
| 3 | 3 | Q, SB, *WC | |||
| 4 | 2 | Julian Reus, Joshua Hartmann, Deniz Almas, | 38.70 | Q, SB, *OG, *WC | |
| 5 | 1 | 38.79 | Q, SB, *WC | ||
| 6 | 1 | 38.79 | Q, SB, *OG, *WC | ||
| 7 | 2 | 38.98 | q, SB, *WC | ||
| 8 | 2 | 39.06[4] | q, NR, *OG, *WC | ||
| 9 | 1 | 39.06[5] | SB, *WC | ||
| 10 | 3 | 39.08 | SB, *WC | ||
| 11 | 1 | José González, Pol Retamal,, | 39.30 | SB, *WC | |
| 12 | 2 | 39.34 | SB | ||
| 13 | 3 | 39.55 | SB | ||
| 14 | 1 | 39.59 | SB | ||
| 15 | 3 | 40.01 | SB | ||
| 16 | 2 | 40.54 | |||
| 1 | |||||
| 3 | , Diogo Antunes,, | ||||
| Rank | Nation | Athletes | Time | Notes | |
|---|---|---|---|---|---|
| Fausto Desalu, Marcell Jacobs, Davide Manenti, Filippo Tortu | 39.21 | ||||
| Ryuichiro Sakai, Ryota Suzuki, Daisuke Miyamoto, Hiroki Yanagita | 39.42 | ||||
| Simon Hansen, Tazana Kamanga-Dyrbak, Kojo Musah, Frederik Schou-Nielsen | 39.56 | ||||
| Joris van Gool, Taymir Burnet, Hensley Paulina, Chris Garia | DNF | ||||
| Michael Pohl, Joshua Hartmann, Roy Schmidt, | DNF | ||||
| Rodrigo do Nascimento, Felipe dos Santos, Derick Silva, Paulo André de Oliveira | DQ | R17.3.1 | |||
| Sean Safo-Antwi, Benjamin Azamati-Kwaku, Joseph Oduro Manu, Joseph Paul Amoah | DQ | R24.7 | |||
| Thando Dlodlo, Gift Leotlela, Clarence Munyai, Akani Simbine | DQ | Doping offence[7] |