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

The heats were held on 28 July at 10:10.[3]

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

The semifinals were held on 28 July at 18:35.[4]

The final was held on 29 July at 18:13.[5]

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