Swimming at the 2011 World Aquatics Championships – Men's 100 metre butterfly
The men's 100 metre butterfly competition of the swimming events at the 2011 World Aquatics Championships was held on July 29 with the heats and the semifinals and July 30 with the final.
Records
Prior to the competition, the existing world and championship records were as follows.| Name | Nation | Time | Location | Date | |
| World record Championship record | Michael Phelps | 49.82 | Rome | August 1, 2009 |
Results
Heats
66 swimmers participated in 9 heats.| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 8 | 5 | Tyler McGill | Q | ||
| 2 | 7 | 3 | Takuro Fujii | Q | ||
| 3 | 9 | 5 | Geoff Huegill | Q | ||
| 4 | 8 | 7 | Jason Dunford | Q | ||
| 5 | 8 | 4 | Michael Phelps | Q | ||
| 6 | 7 | 6 | Konrad Czerniak | Q | ||
| 7 | 7 | 5 | Yevgeny Korotyshkin | Q | ||
| 8 | 7 | 4 | Benjamin Starke | Q | ||
| 9 | 9 | 3 | Joeri Verlinden | Q | ||
| 10 | 9 | 8 | Sam Ashby | Q | ||
| 11 | 9 | 6 | László Cseh | Q | ||
| 12 | 9 | 1 | Peter Mankoč | Q | ||
| 13 | 6 | 6 | Chad le Clos | Q | ||
| 14 | 8 | 6 | Steffen Deibler | Q | ||
| 15 | 9 | 7 | Lars Frölander | Q | ||
| 16 | 8 | 1 | Paweł Korzeniowski | Q | ||
| 17 | 6 | 3 | Francois Heersbrandt | |||
| 18 | 9 | 2 | Milorad Čavić | |||
| 19 | 7 | 2 | Antony James | |||
| 20 | 8 | 8 | Ryan Pini | |||
| 21 | 6 | 2 | Joseph Bartoch | |||
| 22 | 6 | 7 | Simão Morgado | |||
| 23 | 6 | 8 | Pavel Sankovich | |||
| 24 | 7 | 7 | Ivan Lenđer | |||
| 25 | 7 | 1 | Michael Rock | |||
| 26 | 8 | 2 | Kaio Almeida | |||
| 27 | 5 | 1 | Ben Hockin | |||
| 28 | 8 | 3 | Zhou Jiawei | |||
| 29 | 5 | 3 | Lorenzo Benatti | |||
| 30 | 7 | 8 | Nikita Konovalov | |||
| 31 | 5 | 2 | Vytautas Janušaitis | |||
| 32 | 5 | 6 | Dominik Meichtry | NR | ||
| 33 | 6 | 1 | Mario Todorović | |||
| 34 | 6 | 5 | Octavio Alesi | |||
| 35 | 6 | 4 | Wu Peng | |||
| 36 | 4 | 3 | Ham Jong-Hun | |||
| 37 | 5 | 7 | Jan Sefl | |||
| 38 | 5 | 8 | Shaune Fraser | |||
| 39 | 5 | 5 | Hoàng Quý Phước | |||
| 40 | 4 | 4 | Bradley Ally | |||
| 41 | 4 | 5 | Hsu Chi-Chieh | |||
| 42 | 4 | 2 | Yeugeniy Lazuka | |||
| 43 | 4 | 6 | Alex Hernandez Medina | |||
| 44 | 5 | 4 | Stefanos Dimitriadis | |||
| 45 | 4 | 1 | Joshua McLeod | |||
| 46 | 4 | 7 | Rami Anis | |||
| 47 | 2 | 4 | Brad Hamilton | NR | ||
| 48 | 3 | 5 | Marcelino Richaards | |||
| 49 | 2 | 5 | Ifalemi Paea | |||
| 50 | 4 | 8 | Saeed Ashtiani | |||
| 51 | 3 | 1 | Rommie Benjamin | |||
| 52 | 3 | 4 | Edgar Crespo | |||
| 53 | 3 | 2 | Javier Hernandez | |||
| 54 | 3 | 3 | Donny Utomo | |||
| 55 | 3 | 7 | Oluseyi Fatayi-Williams | |||
| 56 | 3 | 6 | Joao Matias | |||
| 57 | 3 | 8 | Sofyan El Gadi | |||
| 58 | 2 | 3 | Andrey Molchanov | |||
| 59 | 2 | 1 | Iohanad Dheyaa | |||
| 60 | 2 | 6 | Alban Laye-Joseph Diop | |||
| 61 | 2 | 7 | Amer Ali | |||
| 62 | 2 | 2 | Adama Ouedraogo | |||
| 63 | 2 | 8 | Khalid Ismaeel Alibaba | |||
| 64 | 1 | 3 | Beni-Bertrand Binobagira | |||
| 65 | 1 | 4 | Janvier Niyonkuru | |||
| 1 | 5 | Fiseha Hailu | DSQ |
Semifinals
The semifinals were held at 19:01.Semifinal 1
Semifinal 2
Final
The final was held at 18:42.| Rank | Lane | Name | Nationality | Time | Notes |
| 4 | Michael Phelps | 50.71 | |||
| 5 | Konrad Czerniak | 51.15 | NR | ||
| 3 | Tyler McGill | 51.26 | |||
| 4 | 1 | Jason Dunford | 51.59 | ||
| 5 | 6 | Takuro Fujii | 51.75 | ||
| 6 | 2 | Yevgeny Korotyshkin | 51.86 | ||
| 7 | 8 | Joeri Verlinden | 52.21 | ||
| 8 | 7 | Geoff Huegill | 52.36 |