| Event: | Girls' 400 metre hurdles |
| Games: | 2018 Summer Youth |
| Venue: | Parque Polideportivo Roca |
| Date: | 13, 16 October |
| Competitors: | 19 |
| Nations: | 19 |
| Gold: | Valeria Cabezas |
| Goldnoc: | COL |
| Silver: | Loubna Benhadja |
| Silvernoc: | ALG |
| Bronze: | Carla García |
| Bronzenoc: | ESP |
| Prev: | 2014 |
| Next: | 2026 |
The girls' 400 metre hurdles metres competition at the 2018 Summer Youth Olympics was held on 13 and 16 October, at the Parque Polideportivo Roca.
All times are in local time (UTC-3).
| Date | Time | Round | ||||
|---|---|---|---|---|---|---|
| 13 October 2018 | 14:50 | Stage 1 | ||||
| style=background:lemonchiffon | 16 October 2018 | style=background:lemonchiffon | 14:55 | style=background:lemonchiffon | Stage 2 |
| Rank | Heat | Lane | Athlete | Nation | Result | Notes | |
|---|---|---|---|---|---|---|---|
| 1 | 1 | 8 | Valeria Cabezas | QH3 | |||
| 2 | 3 | 5 | Jéssica Moreira | QH3, | |||
| 3 | 1 | 3 | Carla García | 1:00.84 | QH3 | ||
| 4 | 3 | 7 | Emma Silvestri | 1:00.88 | QH3 | ||
| 5 | 2 | 4 | Julia Lovsin | 1:00.95 | QH3 | ||
| 6 | 1 | 4 | Loubna Benhadja | 1:00.98 | QH3 | ||
| 7 | 2 | 3 | Gisèle Wender | 1:01.16 | QH3 | ||
| 8 | 3 | 4 | Yara Amador | 1:01.63 | QH3 | ||
| 9 | 3 | 2 | Kristýna Korelová | 1:01.84 | QH2 | ||
| 10 | 1 | 2 | Lena Pressler | 1:01.85 | QH2 | ||
| 11 | 2 | 7 | Vishnu Priya Jayaprakasan | 1:02.56 | QH2 | ||
| 12 | 2 | 2 | Yang Jui-hsuan | 1:02.65 | QH2 | ||
| 13 | 1 | 6 | Miriam Daly | 1:02.72 | QH2 | ||
| 14 | 2 | 5 | Kia Laisi | 1:03.23 | QH2 | ||
| 15 | 3 | 3 | Gontse Morake | 1:04.35 | QH1 | ||
| 16 | 3 | 6 | Ariana Rivera | 1:05.72 | QH1, | ||
| 17 | 1 | 7 | Phailin Khonepaseuth | 1:09.68 | QH1, | ||
| 18 | 1 | 5 | Evedieu Samba | 1:10.63 | QH1, | ||
| 19 | 2 | 6 | Aminata Kaboré | 1:12.05 | QH1 |
| Rank | Heat | Lane | Athlete | Nation | Result | Notes | |
|---|---|---|---|---|---|---|---|
| 1 | 3 | 3 | Valeria Cabezas | ||||
| 2 | 3 | 2 | Loubna Benhadja | ||||
| 3 | 3 | 8 | Julia Lovsin | ||||
| 4 | 3 | 1 | Yara Amador | ||||
| 5 | 3 | 4 | Carla García | ||||
| 6 | 1 | 3 | Gontse Morake | ||||
| 7 | 3 | 6 | Emma Silvestri | 1:00.62 | |||
| 8 | 3 | 7 | Gisèle Wender | 1:01.02 | |||
| 9 | 2 | 3 | Yang Jui-hsuan | 1:01.04 | |||
| 10 | 2 | 6 | Kristýna Korelová | 1:01.13 | |||
| 11 | 2 | 4 | Lena Pressler | 1:01.33 | |||
| 12 | 2 | 5 | Vishnu Priya Jayaprakasan | 1:01.92 | |||
| 13 | 2 | 8 | Miriam Daly | 1:02.15 | |||
| 14 | 1 | 6 | Ariana Rivera | 1:06.03 | |||
| 15 | 3 | 5 | Jéssica Moreira | 1:06.13 | |||
| 16 | 1 | 5 | Evedieu Samba | 1:08.15 | |||
| 17 | 1 | 7 | Aminata Kaboré | 1:08.26 | |||
| 18 | 1 | 4 | Phailin Khonepaseuth | 1:09.49 | |||
| 2 | 7 | Kia Laisi |
| Rank | Athlete | Nation | Stage 1 | Stage 2 | Total | |
|---|---|---|---|---|---|---|
| Valeria Cabezas | 1:57.58 | |||||
| Loubna Benhadja | 1:00.98 | 2:00.68 | ||||
| Carla García | 1:00.84 | 2:00.76 | ||||
| Julia Lovsin | 1:00.95 | 2:00.84 | ||||
| Emma Silvestri | 1:00.88 | 1:00.62 | 2:01.50 | |||
| Yara Amador | 1:01.63 | 2:01.54 | ||||
| Gisèle Wender | 1:01.16 | 1:01.02 | 2:02.18 | |||
| Kristýna Korelová | 1:01.84 | 1:01.13 | 2:02.97 | |||
| Lena Pressler | 1:01.85 | 1:01.33 | 2:03.18 | |||
| 10 | Yang Jui-hsuan | 1:02.65 | 1:01.04 | 2:03.69 | ||
| 11 | Gontse Morake | 1:04.35 | 2:04.30 | |||
| 12 | Vishnu Priya Jayaprakasan | 1:02.56 | 1:01.92 | 2:04.48 | ||
| 13 | Miriam Daly | 1:02.72 | 1:02.15 | 2:04.87 | ||
| 14 | Jéssica Moreira | 1:06.13 | 2:05.54 | |||
| 15 | Ariana Rivera | 1:05.72 | 1:06.03 | 2:11.75 | ||
| 16 | Evedieu Samba | 1:10.63 | 1:08.15 | 2:18.78 | ||
| 17 | Phailin Khonepaseuth | 1:09.68 | 1:09.49 | 2:19.17 | ||
| 18 | Aminata Kaboré | 1:12.05 | 1:08.26 | 2:20.31 | ||
| Kia Laisi | 1:03.23 |