Semifinal
dimanche 6 août 2017, 20h40 GMT – 20h40 GMT
| Nom | Équipe | Temps | |
|---|---|---|---|
| 1 |  Steven Gardiner | Bahamas | 43.89″ |
| 2 |  Nathon Allen | Jamaica | + 0.3″ |
| 3 |  Wayde Van Niekerk | South Africa | + 0.33″ |
| 4 |  Isaac Makwala | Botswana | + 0.41″ |
| 5 | Baboloki Thebe | Botswana | + 0.44″ |
| 6 |  Fred Kerley | United States | + 0.62″ |
| 7 | Demish Gaye | Jamaica | + 0.66″ |
| 8 |  Abdalelah Haroun | Qatar | + 0.75″ |
| 9 | Matthew Hudson-Smith | Great Britain | + 0.85″ |
| 10 | Gil Roberts | United States | + 0.95″ |
| 11 |  Kevin Borlée | Belgium | + 1.21″ |
| 12 | Wilbert London | United States | + 1.23″ |
| 13 | Jamal Walton | Cayman Islands | + 1.27″ |
| 14 |  Oscar Husillos | Spain | + 1.27″ |
| 15 | Lalonde Gordon | Trinidad & Tobago | + 1.31″ |
| 16 | Jonathan Borlee | Belgium | + 1.34″ |
| 17 |  Pavel Maslak | Czech Republic | + 1.35″ |
| 18 |  Rafal Omelko | Poland | + 1.48″ |
| 19 | Brian Gregan | Ireland | + 1.53″ |
| 20 | LaShawn Merritt | United States | + 1.63″ |
| 21 | Machel Cedenio | Trinidad & Tobago | + 2.02″ |
| 22 | Boniface Ontuga Mweresa | Kenya | + 2.04″ |
| 23 |  Davide Re | Italy | + 2.06″ |
| 24 | Dwayne Cowan | Great Britain | + 2.07″ |