2012 World Junior Championships in Athletics – Women's 400 metres
The women's 400 metres at the 2012 World Junior Championships in Athletics was held at the Estadi Olímpic Lluís Companys on 11, 12, and 13 July.Medalists
Records
, the existing world junior and championship records were as follows.Results
Heats
Qualification: first 3 of each heat plus the 6 fastest times qualified
| Rank | Heat | Lane | Name | Nationality | Time | Note |
| 1 | 1 | 4 | Ashley Spencer | | 52.58 | Q |
| 2 | 4 | 9 | Shaunae Miller | | 52.71 | Q |
| 3 | 4 | 6 | Patrycja Wyciszkiewicz | | 52.76 | Q, NJ |
| 4 | 4 | 7 | Olivia James | | 52.86 | Q, SB |
| 5 | 1 | 3 | Ekaterina Renzhina | | 52.92 | Q, PB |
| 6 | 5 | 4 | Chrisann Gordon | | 52.99 | Q |
| 7 | 5 | 6 | Kadecia Baird | | 53.29 | Q |
| 8 | 6 | 7 | Erika Rucker | | 53.32 | Q |
| 9 | 3 | 6 | Bianca Răzor | | 53.44 | Q |
| 10 | 6 | 8 | Justine Palframan | | 53.53 | Q |
| 11 | 1 | 9 | Maike Schachtschneider | | 53.57 | Q, PB |
| 12 | 4 | 3 | Ella Räsänen | | 53.77 | q, SB |
| 13 | 6 | 5 | Adelina Pastor | | 53.85 | Q |
| 14 | 2 | 6 | Rashan Brown | | 54.02 | Q |
| 15 | 4 | 4 | Flavia Battaglia | | 54.03 | q, PB |
| 16 | 5 | 8 | Abbey de la Motte | | 54.03 | Q, PB |
| 17 | 1 | 7 | Joanna Mills | | 54.17 | q, SB |
| 18 | 3 | 9 | Morgan Mitchell | | 54.19 | Q, PB |
| 19 | 3 | 8 | Bianka Kéri | | 54.34 | Q |
| 20 | 2 | 5 | Alina Galitskaya | | 54.55 | Q |
| 21 | 1 | 5 | Grace Claxton | | 54.65 | q, NJ |
| 22 | 5 | 7 | Viktoriya Tkachuk | | 54.67 | q |
| 23 | 1 | 6 | Simone Werner | | 54.70 | q, PB |
| 24 | 5 | 9 | Carina Schrempf | | 54.73 | PB |
| 25 | 4 | 8 | Rivinilda Mentai | | 54.83 | NJ |
| 26 | 6 | 4 | Kateryna Slyusarenko | | 54.88 | |
| 27 | 3 | 3 | Janet Seeliger | | 55.00 | |
| 28 | 2 | 9 | Jie Chen | | 55.04 | Q |
| 29 | 6 | 6 | Ines Futterknecht | | 55.16 | |
| 30 | 3 | 5 | Christine Botlogetswe | | 55.26 | PB |
| 31 | 4 | 5 | Qingqing Wu | | 55.37 | |
| 32 | 2 | 7 | Gunta Latiševa-Cudare | | 55.57 | |
| 33 | 2 | 8 | Olga Andreyeva | | 55.96 | |
| 34 | 3 | 4 | Danielle Alakija | | 56.69 | |
| 35 | 6 | 3 | Jonel Lacey | | 58.87 | PB |
| 36 | 2 | 2 | Princilla Tshabu Amisi | | 1:05.85 | PB |
| 37 | 2 | 4 | Reloliza Saimon | | 1:09.88 | SB |
| – | 5 | 5 | Lucy Fortune | | – | DSQ |
| – | 5 | 3 | Regina Tavera | | – | DSQ |
| – | 6 | 9 | Alexandra Courtnall | | – | DSQ |
| – | 2 | 3 | Florence Uwakwe | | – | DNS |
| – | 1 | 8 | Melisa Torres | | – | DNS |
| – | 3 | 7 | Omolara Omotosho | | – | DNS |
Semi-Finals
Qualification: first 2 of each heat plus the 2 fastest times qualified
| Rank | Heat | Lane | Name | Nationality | Time | Note |
| 1 | 1 | 6 | Erika Rucker | | 52.05 | Q, PB |
| 2 | 3 | 5 | Ashley Spencer | | 52.24 | Q |
| 3 | 1 | 4 | Kadecia Baird | | 52.40 | Q |
| 4 | 1 | 7 | Justine Palframan | | 52.65 | q |
| 5 | 1 | 5 | Chrisann Gordon | | 52.70 | q |
| 6 | 3 | 9 | Olivia James | | 52.71 | Q, SB |
| 7 | 2 | 4 | Shaunae Miller | | 52.75 | Q |
| 8 | 2 | 6 | Bianca Răzor | | 52.87 | Q |
| 9 | 3 | 4 | Rashan Brown | | 52.88 | |
| 10 | 2 | 7 | Ekaterina Renzhina | | 52.97 | |
| 11 | 3 | 7 | Patrycja Wyciszkiewicz | | 53.04 | |
| 12 | 1 | 9 | Adelina Pastor | | 53.28 | SB |
| 13 | 2 | 5 | Morgan Mitchell | | 53.88 | PB |
| 14 | 1 | 8 | Abbey de la Motte | | 53.90 | PB |
| 15 | 3 | 2 | Ella Räsänen | | 54.40 | |
| 16 | 1 | 2 | Grace Claxton | | 54.42 | NJ |
| 17 | 2 | 9 | Maike Schachtschneider | | 54.49 | |
| 18 | 1 | 3 | Joanna Mills | | 54.52 | |
| 19 | 3 | 8 | Jie Chen | | 54.67 | |
| 20 | 2 | 8 | Bianka Kéri | | 54.68 | |
| 21 | 2 | 2 | Flavia Battaglia | | 54.82 | |
| 22 | 3 | 6 | Alina Galitskaya | | 54.98 | |
| 23 | 2 | 3 | Viktoriya Tkachuk | | 55.02 | |
| 24 | 3 | 3 | Simone Werner | | 55.85 | |
Final
Participation
According to an unofficial count, 40 athletes from 30 countries participated in the event.
