The women's 400 metres hurdles event at the 2017 European Athletics U23 Championships was held in Bydgoszcz, Poland, at Zdzisław Krzyszkowiak Stadium on 14, 15 and 16 July.
| Gold | Ayomide Folorunso | |
| Silver | Jessica Turner | |
| Bronze | Arna Stefanía Guðmundsdóttir |
14 July[1]
Qualification rule: First 3 (Q) and the next 4 fastest (q) qualified for the semifinals.
| Rank | Heat | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|
| 1 | 4 | align=left | align=left | 56.96 | Q | |||
| 2 | 1 | align=left | align=left | 57.27 | Q | |||
| 3 | 1 | align=left | align=left | 57.45 | Q | |||
| 4 | 3 | align=left | align=left | 57.48 | Q | |||
| 5 | 4 | align=left | align=left | 57.78 | Q | |||
| 6 | 4 | align=left | align=left | 57.86 | Q, PB | |||
| 7 | 2 | align=left | align=left | 58.12 | Q | |||
| 8 | 3 | align=left | align=left | 58.20 | Q | |||
| 9 | 2 | align=left | align=left | 58.54 | Q | |||
| 10 | 4 | align=left | align=left | 58.59 | q | |||
| 11 | 1 | align=left | align=left | 58.73 | Q | |||
| 12 | 3 | align=left | align=left | 58.78 | Q | |||
| 13 | 2 | align=left | align=left | 58.80 | Q | |||
| 14 | 3 | align=left | align=left | 58.85 | q, SB | |||
| 15 | 3 | align=left | align=left | 58.98 | q | |||
| 16 | 4 | align=left | align=left | 59.66 | q | |||
| 17 | 2 | align=left | align=left | 59.77 | ||||
| 18 | 1 | align=left | align=left | 59.99 | ||||
| 19 | 2 | align=left | align=left | |||||
| 20 | 4 | align=left | align=left | |||||
| 21 | 2 | align=left | align=left | |||||
| 22 | 4 | align=left | align=left | |||||
| 23 | 3 | align=left | align=left | |||||
| 24 | 3 | align=left | align=left | |||||
| 25 | 1 | align=left | align=left | |||||
| 26 | 1 | align=left | align=left | |||||
| 26 | 2 | align=left | align=left | |||||
| 27 | 2 | align=left | align=left | |||||
| 3 | align=left | align=left | R162.7[2] | |||||
| 1 | align=left | align=left |
15 July[3]
Qualification rule: First 3 (Q) and the next 2 fastest (q) qualified for the final.
| Rank | Heat | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|
| 1 | 1 | align=left | align=left | 56.35 | Q, SB | |||
| 2 | 2 | align=left | align=left | 56.92 | Q | |||
| 3 | 2 | align=left | align=left | 56.99 | Q, SB | |||
| 4 | 1 | align=left | align=left | 57.02 | Q | |||
| 5 | 2 | align=left | align=left | 57.32 | Q | |||
| 6 | 1 | align=left | align=left | 57.34 | Q | |||
| 7 | 1 | align=left | align=left | 57.35 | q | |||
| 8 | 1 | align=left | align=left | 57.44 | q | |||
| 9 | 2 | align=left | align=left | 57.64 | PB | |||
| 10 | 2 | align=left | align=left | 57.68 | PB | |||
| 11 | 1 | align=left | align=left | 58.07 | PB | |||
| 12 | 2 | align=left | align=left | 58.14 | ||||
| 13 | 2 | align=left | align=left | 58.22 | ||||
| 14 | 2 | align=left | align=left | 58.50 | ||||
| 15 | 1 | align=left | align=left | 58.75 | ||||
| 16 | 1 | align=left | align=left | 58.78 |
16 July[4]
| Rank | Lane | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|
| 5 | align=left | align=left | 55.82 | SB | ||||
| 8 | align=left | align=left | 56.08 | PB | ||||
| 4 | align=left | align=left | 56.37 | SB | ||||
| 4 | 2 | align=left | align=left | 56.94 | ||||
| 5 | 7 | align=left | align=left | 57.12 | ||||
| 6 | 3 | align=left | align=left | 57.43 | ||||
| 7 | 6 | align=left | align=left | 57.74 | ||||
| 8 | 1 | align=left | align=left | 59.53 |