# Swimming at the 2011 World Aquatics Championships – Women's 100 metre butterfly

The women's 100 metre butterfly competition of the swimming events at the 2011 World Aquatics Championships took place on 24 and 25 July. The heats and semifinals took place on 24 July and the final was held on 25 July.

## Records

Prior to the competition, the existing world and championship records were as follows.
| | Name | Nation | Time | Location | Date |
| World record Championship record | Sarah Sjöström | Sweden | 56.06 | Rome | 27 July 2009 |

## Results
### Heats

47 swimmers participated in 6 heats, qualified swimmers are listed:
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | 5 | Dana Vollmer | United States | 56.97 | Q |
| 2 | 6 | 4 | Alicia Coutts | Australia | 57.49 | Q |
| 3 | 4 | 5 | Jemma Lowe | Great Britain | 57.81 | Q |
| 4 | 4 | 2 | Jessicah Schipper | Australia | 57.86 | Q |
| 5 | 6 | 2 | Lu Ying | China | 57.93 | Q |
| 6 | 4 | 4 | Sarah Sjöström | Sweden | 58.10 | Q |
| 7 | 4 | 3 | Ellen Gandy | Great Britain | 58.32 | Q |
| 7 | 5 | 6 | Jeanette Ottesen | Denmark | 58.32 | Q |
| 9 | 6 | 5 | Liu Zige | China | 58.44 | Q |
| 10 | 5 | 4 | Christine Magnuson | United States | 58.49 | Q |
| 11 | 5 | 3 | Inge Dekker | Netherlands | 58.53 | Q |
| 12 | 4 | 6 | Katerine Savard | Canada | 58.59 | Q |
| 13 | 6 | 6 | Yuka Kato | Japan | 58.70 | Q |
| 14 | 6 | 3 | Therese Alshammar | Sweden | 58.71 | Q |
| 15 | 5 | 2 | Tao Li | Singapore | 58.89 | Q |
| 15 | 6 | 8 | Irina Bespalova | Russia | 58.89 | Q |
| 17 | 4 | 7 | Vanessa Mohr | South Africa | 58.96 | |
| 17 | 4 | 8 | Sina Sutter | Germany | 58.96 | |
| 19 | 2 | 3 | Otylia Jędrzejczak | Poland | 59.00 | |
| 20 | 5 | 8 | Audrey Lacroix | Canada | 59.02 | |
| 21 | 5 | 1 | Daynara de Paula | Brazil | 59.24 | |
| 22 | 6 | 7 | Kristel Vourna | Greece | 59.27 | |
| 23 | 3 | 6 | Judit Ignacio Sorribes | Spain | 59.52 | |
| 24 | 5 | 7 | Amit Ivry | Israel | 59.56 | |
| 25 | 3 | 4 | Natsumi Hoshi | Japan | 59.63 | |
| 26 | 3 | 2 | Hannah Wilson | Hong Kong | 59.78 | |
| 26 | 3 | 8 | Triin Aljand | Estonia | 59.78 | |
| 28 | 2 | 5 | Ingvild Snildal | Norway | 59.80 | |
| 29 | 2 | 4 | Birgit Koschischek | Austria | 59.84 | |
| 30 | 2 | 6 | Katarina Listopadova | Slovakia | 59.87 | |
| 31 | 3 | 1 | Kimberly Buys | Belgium | 59.88 | |
| 32 | 6 | 1 | Sara Oliveira | Portugal | 59.93 | |
| 33 | 3 | 5 | Sara Isaković | Slovenia | 1:00.23 | |
| 34 | 3 | 3 | Ilaria Bianchi | Italy | 1:00.36 | |
| 35 | 2 | 2 | Rita Medrano | Mexico | 1:00.55 | |
| 36 | 4 | 1 | Eszter Dara | Hungary | 1:00.69 | |
| 37 | 2 | 7 | Se-Hyeon An | South Korea | 1:00.76 | |
| 38 | 2 | 1 | Iris Rosenberger | Turkey | 1:00.99 | |
| 39 | 3 | 7 | Sophia Batchelor | New Zealand | 1:01.92 | |
| 40 | 1 | 4 | Jasmine Alkhaldi | Philippines | 1:03.69 | |
| 41 | 1 | 3 | Loreen Whitfield | American Samoa | 1:04.82 | |
| 42 | 1 | 5 | Marie Laura Meza | Costa Rica | 1:05.05 | |
| 43 | 1 | 6 | Noel Borshi | Albania | 1:05.71 | |
| 43 | 1 | 7 | Dalia Torrez | Nicaragua | 1:05.71 | |
| 45 | 1 | 1 | Simona Muccioli | San Marino | 1:06.45 | |
| 46 | 1 | 2 | Dorian McMenemy | Dominican Republic | 1:06.58 | |
| 47 | 1 | 8 | Debra Daniel | Micronesia | 1:14.51 | |

#### Reserve place swimoff

As two swimmers had the same time in the heats at place 17 they had to participate in a swimoff to determine the first semifinal reserve swimmer.
| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Vanessa Mohr | South Africa | 58.66 | |
| 2 | 5 | Sina Sutter | Germany | 59.47 | |

### Semifinals

The semifinals were held on 24 July at 18:00.

#### Semifinal 1

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 3 | Sarah Sjöström | Sweden | 57.29 | Q |
| 2 | 4 | Alicia Coutts | Australia | 57.41 | Q |
| 3 | 5 | Jessicah Schipper | Australia | 57.95 | Q |
| 4 | 7 | Katerine Savard | Canada | 58.07 | |
| 5 | 1 | Therese Alshammar | Sweden | 58.20 | |
| 6 | 6 | Jeanette Ottesen | Denmark | 58.24 | |
| 7 | 2 | Christine Magnuson | United States | 58.59 | |
| 8 | 8 | Irina Bespalova | Russia | 59.02 | |

#### Semifinal 2

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Dana Vollmer | United States | 56.47 | Q, AM |
| 2 | 3 | Lu Ying | China | 57.18 | Q |
| 3 | 5 | Jemma Lowe | Great Britain | 57.57 | Q |
| 4 | 2 | Liu Zige | China | 57.85 | Q |
| 5 | 6 | Ellen Gandy | Great Britain | 57.97 | Q |
| 6 | 7 | Inge Dekker | Netherlands | 58.70 | |
| 7 | 1 | Yuka Kato | Japan | 58.71 | |
| 8 | 8 | Tao Li | Singapore | 58.78 | |

### Final

The final was held at 18:02.
| Rank | Lane | Name | Nationality | Time |
| | 4 | Dana Vollmer | United States | 56.87 |
| | 6 | Alicia Coutts | Australia | 56.94 |
| | 5 | Lu Ying | China | 57.06 |
| 4 | 3 | Sarah Sjöström | Sweden | 57.38 |
| 5 | 8 | Ellen Gandy | Great Britain | 57.55 |
| 6 | 7 | Liu Zige | China | 57.57 |
| 7 | 1 | Jessicah Schipper | Australia | 57.95 |
| 8 | 2 | Jemma Lowe | Great Britain | 57.96 |