The Women's 400 metres event at the 2011 European Athletics U23 Championships was held in Ostrava, Czech Republic, at Městský stadion on 14 and 16 July.
| Gold | Olga Topilskaya | |
| Silver | Yuliya Terekhova | |
| Bronze | Lena Schmidt |
16 July 2011 / 16:30
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| align=left | align=left | 6 | 0.178 | 51.45 | |||||
| align=left | align=left | 4 | 0.271 | 52.63 | |||||
| align=left | align=left | 3 | 0.202 | 52.66 | |||||
| 4 | align=left | align=left |  | 7 | 0.238 | 53.08 | |||
| 5 | align=left | align=left |  | 5 | 0.169 | 53.43 | |||
| 6 | align=left | align=left | 8 | 53.86 | |||||
| 7 | align=left | align=left |  | 2 | 0.173 | 54.18 | |||
| align=left | align=left | 1 | F1 | DQ R 162.7 |
Qualified: First 2 in each heat (Q) and 2 best performers (q) advance to the Final
| Rank | Name | Nationality | Time | Notes | |||
|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 51.89 | Q | |||
| 2 | align=left | align=left | 52.69 | Q | |||
| 3 | align=left | align=left | 52.75 | Q | |||
| 4 | align=left | align=left | | 53.06 | Q | ||
| 5 | align=left | align=left | 53.08 | Q PB | |||
| 6 | align=left | align=left | | 53.11 | Q | ||
| 7 | align=left | align=left | 53.44 | q | |||
| 8 | align=left | align=left | | 53.51 | q | ||
| 9 | align=left | align=left | 53.99 | PB | |||
| 10 | align=left | align=left | | 54.00 | |||
| 11 | align=left | align=left |  | 54.01 | |||
| 12 | align=left | align=left | 54.09 | ||||
| 13 | align=left | align=left | | 54.14 | |||
| 14 | align=left | align=left | 54.15 | ||||
| 15 | align=left | align=left | 54.18 | ||||
| 15 | align=left | align=left |  | 54.18 | |||
| 17 | align=left | align=left | 54.26 | ||||
| 18 | align=left | align=left |  | 54.53 | |||
| 19 | align=left | align=left | | 54.71 | SB | ||
| 20 | align=left | align=left | 55.13 | ||||
| 21 | align=left | align=left |  | 55.18 | |||
| 22 | align=left | align=left |  | 55.36 | |||
| 23 | align=left | align=left |  | 57.19 |
14 July 2011 / 18:45
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 5 | 0.227 | 52.75 | Q | |||
| 2 | align=left | align=left | 3 | 0.215 | 53.08 | Q PB | |||
| 3 | align=left | align=left | | 6 | 0.240 | 54.00 | |||
| 4 | align=left | align=left | | 4 | 0.228 | 54.01 | |||
| 5 | align=left | align=left | | 7 | 0.245 | 54.18 | |||
| 6 | align=left | align=left | | 1 | 0.274 | 54.53 | |||
| 7 | align=left | align=left | | 8 | 0.192 | 54.71 | SB | ||
| 8 | align=left | align=left | | 2 | 0.196 | 55.36 |
14 July 2011 / 18:52
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 4 | 0.189 | 51.89 | Q | |||
| 2 | align=left | align=left | | 3 | 0.201 | 53.06 | Q | ||
| 3 | align=left | align=left | 5 | 0.152 | 53.44 | q | |||
| 4 | align=left | align=left | 6 | 0.220 | 54.09 | ||||
| 5 | align=left | align=left | 8 | 0.195 | 54.15 | ||||
| 6 | align=left | align=left | 7 | 0.246 | 54.18 | ||||
| 7 | align=left | align=left | | 2 | 0.242 | 55.18 |
14 July 2011 / 18:59
| Rank | Name | Nationality | Lane | Reaction Time | Time | Notes | |||
|---|---|---|---|---|---|---|---|---|---|
| 1 | align=left | align=left | 3 | 0.265 | 52.69 | Q | |||
| 2 | align=left | align=left | | 5 | 0.273 | 53.11 | Q | ||
| 3 | align=left | align=left | | 4 | 0.165 | 53.51 | q | ||
| 4 | align=left | align=left | 2 | 0.254 | 53.99 | PB | |||
| 5 | align=left | align=left | | 6 | 0.279 | 54.14 | |||
| 6 | align=left | align=left | 8 | 0.212 | 54.26 | ||||
| 7 | align=left | align=left | 7 | 0.242 | 55.13 | ||||
| 8 | align=left | align=left | | 1 | 0.458 | 57.19 |
According to an unofficial count, 23 athletes from 17 countries participated in the event.