# Swimming at the 2017 World Aquatics Championships – Men's 100 metre butterfly

The Men's 100 metre butterfly competition at the 2017 World Championships was held on 28 and 29 July 2017.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Michael Phelps (USA) | 49.82 | Rome, Italy | 1 August 2009 |
| Competition record | Michael Phelps (USA) | 49.82 | Rome, Italy | 1 August 2009 |

## Results
### Heats

The heats were held on 28 July at 10:10.
| Rank | Heat | Lane | Name | Nationality | Time | Notes |
| 1 | 6 | 4 | Caeleb Dressel | United States | 50.08 | Q |
| 2 | 6 | 3 | Piero Codia | Italy | 51.09 | Q, NR |
| 3 | 7 | 6 | James Guy | Great Britain | 51.16 | Q |
| 4 | 8 | 4 | Joseph Schooling | Singapore | 51.21 | Q |
| 5 | 8 | 6 | Kristóf Milák | Hungary | 51.23 | Q, WJ |
| 6 | 8 | 5 | Chad le Clos | South Africa | 51.28 | Q |
| 7 | 7 | 3 | Mehdy Metella | France | 51.46 | Q |
| 8 | 6 | 6 | Henrique Martins | Brazil | 51.48 | Q |
| 9 | 7 | 5 | Konrad Czerniak | Poland | 51.50 | Q |
| 10 | 7 | 4 | László Cseh | Hungary | 51.55 | Q |
| 11 | 6 | 5 | Li Zhuhao | China | 51.62 | Q |
| 12 | 7 | 2 | Grant Irvine | Australia | 51.67 | Q |
| 13 | 6 | 7 | Jan Świtkowski | Poland | 51.82 | Q |
| 14 | 8 | 8 | Aleksandr Popkov | Russia | 51.84 | Q |
| 15 | 8 | 2 | David Morgan | Australia | 51.90 | Q |
| 16 | 8 | 3 | Tim Phillips | United States | 51.96 | Q |
| 17 | 7 | 0 | Mathys Goosen | Netherlands | 52.12 | |
| 18 | 8 | 1 | Quah Zheng Wen | Singapore | 52.13 | |
| 19 | 5 | 6 | Sebastian Sabo | Serbia | 52.16 | |
| 20 | 7 | 7 | Yuki Kobori | Japan | 52.17 | |
| 21 | 7 | 8 | Luis Martínez | Guatemala | 52.18 | |
| 22 | 6 | 2 | Marius Kusch | Germany | 52.22 | |
| 23 | 7 | 1 | Daniil Pakhomov | Russia | 52.47 | |
| 24 | 4 | 1 | Kaan Ayar | Turkey | 52.52 | |
| 25 | 6 | 1 | Santiago Grassi | Argentina | 52.59 | |
| 26 | 5 | 2 | Jan Šefl | Czech Republic | 52.65 | |
| 27 | 5 | 0 | Louis Croenen | Belgium | 52.74 | |
| 28 | 7 | 9 | Dylan Carter | Trinidad and Tobago | 52.75 | |
| 29 | 8 | 7 | Pavel Sankovich | Belarus | 52.87 | |
| 30 | 6 | 9 | Andreas Vazaios | Greece | 52.88 | |
| 31 | 4 | 2 | Artyom Kozlyuk | Uzbekistan | 52.95 | |
| 32 | 6 | 8 | Liubomyr Lemeshko | Ukraine | 52.97 | |
| 33 | 6 | 0 | Viktor Bromer | Denmark | 53.01 | |
| 34 | 5 | 3 | Josiah Binnema | Canada | 53.10 | |
| 35 | 8 | 0 | Giacomo Carini | Italy | 53.13 | |
| 36 | 8 | 9 | Marcus Schlesinger | Israel | 53.20 | |
| 37 | 4 | 4 | Adilbek Mussin | Kazakhstan | 53.37 | |
| 38 | 4 | 3 | Nils Liess | Switzerland | 53.50 | |
| 39 | 4 | 7 | Ben Hockin | Paraguay | 53.51 | |
| 40 | 4 | 0 | Riku Pöytäkivi | Finland | 53.62 | |
| 41 | 5 | 1 | Antani Ivanov | Bulgaria | 53.66 | |
| 41 | 5 | 4 | Triady Fauzi Sidiq | Indonesia | 53.66 | |
| 43 | 5 | 5 | Kregor Zirk | Estonia | 53.70 | |
| 44 | 5 | 9 | Brendan Hyland | Ireland | 53.80 | |
| 45 | 4 | 8 | Marcos Lavado | Venezuela | 53.97 | |
| 45 | 5 | 7 | Tadas Duškinas | Lithuania | 53.97 | |
| 47 | 3 | 2 | Chou Wei-liang | Chinese Taipei | 54.31 | |
| 48 | 3 | 3 | Sajan Prakash | India | 54.46 | |
| 49 | 3 | 4 | David Arias | Colombia | 54.48 | |
| 50 | 4 | 9 | José Martínez | Mexico | 54.50 | |
| 51 | 5 | 8 | Omar Eissa | Egypt | 54.59 | |
| 52 | 4 | 5 | Hoàng Quý Phước | Vietnam | 54.76 | |
| 53 | 3 | 5 | Ralph Goveia | Zambia | 54.86 | |
| 54 | 3 | 7 | Christian Sperandio Sánchez | Dominican Republic | 54.98 | |
| 55 | 3 | 6 | Cherantha de Silva | Sri Lanka | 55.09 | |
| 56 | 3 | 0 | Mehdi Ansari | Iran | 55.31 | |
| 57 | 2 | 4 | Mikhail Umnov | Malta | 55.58 | |
| 58 | 3 | 9 | Rami Anis | FINA Independent Athletes | 55.66 | |
| 59 | 3 | 8 | Bryan Alvarez | Costa Rica | 55.85 | |
| 60 | 3 | 1 | Ayman Kelzi | Syria | 56.59 | |
| 61 | 2 | 3 | Jeerakit Soammanus | Thailand | 56.88 | |
| 62 | 2 | 5 | Oumar Toure | Mali | 57.52 | |
| 63 | 2 | 1 | Ifeakachuku Nmor | Nigeria | 57.90 | |
| 64 | 1 | 3 | Abdullah Al-Doori | Iraq | 58.01 | |
| 65 | 2 | 2 | George Jabbour | Honduras | 58.29 | |
| 66 | 1 | 5 | Yacob Al-Khulaifi | Qatar | 58.42 | |
| 67 | 2 | 6 | Hannibal Gaskin | Guyana | 58.69 | |
| 68 | 1 | 4 | Daniel Francisco | Angola | 58.79 | |
| 69 | 1 | 6 | Tanner Poppe | Guam | 1:03.28 | |
| 70 | 2 | 9 | Simanga Dlamini | Eswatini | 1:04.02 | |
| 71 | 2 | 7 | David Roberto | Northern Mariana Islands | 1:06.80 | |
| 72 | 2 | 0 | Dillon Gooding | Saint Vincent and the Grenadines | 1:07.11 | |
| | 4 | 6 | Sam Perry | New Zealand | DNS | DNS |

### Semifinals

The semifinals were held on 28 July at 18:35.

#### Semifinal 1

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 5 | Joseph Schooling | Singapore | 50.78 | Q |
| 2 | 2 | László Cseh | Hungary | 51.16 | Q |
| 3 | 7 | Grant Irvine | Australia | 51.31 | Q |
| 4 | 8 | Tim Phillips | United States | 51.41 | |
| 5 | 4 | Piero Codia | Italy | 51.45 | |
| 6 | 6 | Henrique Martins | Brazil | 51.47 | |
| 7 | 3 | Chad le Clos | South Africa | 51.48 | |
| 8 | 1 | Aleksandr Popkov | Russia | 52.00 | |

#### Semifinal 2

| Rank | Lane | Name | Nationality | Time | Notes |
| 1 | 4 | Caeleb Dressel | United States | 50.07 | Q |
| 2 | 5 | James Guy | Great Britain | 50.67 | Q, NR |
| 3 | 3 | Kristóf Milák | Hungary | 50.77 | Q, WJ, NR |
| 4 | 6 | Mehdy Metella | France | 51.06 | Q, NR |
| 5 | 7 | Li Zhuhao | China | 51.29 | Q |
| 6 | 2 | Konrad Czerniak | Poland | 51.60 | |
| 7 | 8 | David Morgan | Australia | 51.73 | |
| 8 | 1 | Jan Świtkowski | Poland | 52.02 | |

### Final

The final was held on 29 July at 18:13.
| Rank | Lane | Name | Nationality | Time | Notes |
| | 4 | Caeleb Dressel | United States | 49.86 | |
| | 3 | Kristóf Milák | Hungary | 50.62 | WJ, NR |
| | 6 | Joseph Schooling | Singapore | 50.83 | |
| | 5 | James Guy | Great Britain | 50.83 | |
| 5 | 7 | László Cseh | Hungary | 50.92 | |
| 6 | 1 | Li Zhuhao | China | 50.96 | |
| 7 | 8 | Grant Irvine | Australia | 51.00 | |
| 8 | 2 | Mehdy Metella | France | 51.16 | |