2013 World Youth Championships in Athletics – Boys' 400 metres hurdles
The Boys' 400 metres hurdles at the 2013 World Youth Championships in Athletics was held on 10–12 July.
Medalists
| Gold | Silver | Bronze |
| Marvin Williams JAM | Wang Yang CHN | Kenneth Selmon USA |
Records
Prior to the competition, the following records were as follows.| World Youth Best | 49.01 | Ostrava, Czech Republic | 15 July 2007 | |
| Championship Record | 49.01 | Ostrava, Czech Republic | 15 July 2007 | |
| World Youth Leading | 50.75 | Edwardsville, IL, United States | 26 June 2013 |
Heats
Qualification rule: first 3 of each heat and the next 3 fastest qualified.Heat 1
Heat 2
Heat 3
Heat 4
Heat 5
Heat 6
Heat 7
Semifinals
Qualification rule: first 2 of each heat plus the 2 fastest times qualified.Heat 1
| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | Wang Yang | 50.72 | Q | |
| 2 | 6 | Kenneth Selmon | 50.95 | Q | |
| 3 | 3 | Geofrey Kipkoech Cheruiyot | 51.01 | q | |
| 4 | 4 | Naoya Okubo | 52.03 | ||
| 5 | 8 | Matteo Beria | 52.18 | ||
| 6 | 7 | Xavier Coakley | 53.78 | ||
| 7 | 2 | Vladislav Omelchenko | 54.30 | ||
| 8 | 1 | Raouf Jedid | 55.30 |
Heat 2
| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 3 | Marvin Williams | 51.31 | Q | |
| 2 | 4 | Derick Diaz | 51.95 | Q | |
| 3 | 5 | Avotriniaina Rakotoarimiandry | 52.11 | ||
| 4 | 7 | Giuseppe Biondo | 52.45 | ||
| 5 | 6 | Javier Delgado | 52.84 | ||
| 6 | 1 | Mahmoud Reza Moshtagh | 52.88 | Q | |
| 7 | 8 | Mohamed Fares Jlassi | 52.96 | ||
| 8 | 2 | Divan Rossouw | 55.75 |
Heat 3
| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 6 | Okeen Williams | 50.53 | Q | |
| 2 | 5 | Marlon Humphrey | 50.96 | Q | |
| 3 | 4 | Takumu Furuya | 51.0 | q | |
| 4 | 7 | Ryan Wallis | 52.21 | ||
| 5 | 3 | Rai Benjamin | 52.36 | ||
| 6 | 1 | Hanno Coetzer | 53.60 | ||
| 7 | 8 | Khalid Mohammed Al-Shahrani | 54.26 | ||
| 8 | 2 | Daniel Brady | 54.78 |
Final
| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Marvin Williams | 50.39 | Q | |
| 2 | 6 | Wang Yang | 50.78 | ||
| 3 | 5 | Kenneth Selmon | 51.30 | ||
| 4 | 1 | Takumu Furuya | 51.58 | ||
| 5 | 7 | Derick Diaz | 51.76 | ||
| 2 | Geofrey Kipkoech Cheruiyot | DNF | |||
| 3 | Okeen Williams | DNF | |||
| 8 | Marlon Humphrey | DNS |