# Swimming at the 2024 World Aquatics Championships – Mixed 4 × 100 metre medley relay

The Mixed 4 × 100 metre medley relay competition at the 2024 World Aquatics Championships was held on 14 February 2024.

## Records

Prior to the competition, the existing world and championship records were as follows.
| World record | Great Britain | 3:37.58 | Tokyo, Japan | 31 July 2021 |
| Competition record | United States | 3:38.56 | Budapest, Hungary | 26 July 2017 |

## Results
### Heats

The heats were started at 10:47.
| Rank | Heat | Lane | Nation | Swimmers | Time | Notes |
| 1 | 4 | 3 | Great Britain | Medi Harris (1:00.62) James Wilby (1:00.00) Duncan Scott (52.15) Anna Hopkin (52.73) | 3:45.50 | Q |
| 2 | 3 | 4 | Australia | Bradley Woodward (53.89) Sam Williamson (59.49) Alexandria Perkins (57.47) Abbey Harkin (54.69) | 3:45.54 | Q |
| 3 | 4 | 5 | United States | Jack Aikins (53.49) Jake Foster (59.29) Rachel Klinker (58.18) Addison Sauickie (54.97) | 3:45.93 | Q |
| 4 | 4 | 7 | Greece | Apostolos Christou (53.67) Arkadios Aspougalis (1:00.54) Anna Ntountounaki (57.37) Theodora Drakou (54.96) | 3:46.54 | Q |
| 5 | 4 | 2 | Poland | Ksawery Masiuk (53.09) Dominika Sztandera (1:07.28) Adrian Jaśkiewicz (51.63) Kornelia Fiedkiewicz (54.57) | 3:46.57 | Q |
| 6 | 4 | 6 | Japan | Osamu Kato (54.30) Ikuru Hiroshima (1:00.44) Chiharu Iitsuka (58.13) Nagisa Ikemoto (54.05) | 3:46.92 | Q |
| 7 | 3 | 6 | Sweden | Hanna Rosvall (1:01.21) Erik Persson (1:00.52) Louise Hansson (56.99) Robin Hanson (48.78) | 3:47.50 | Q |
| 8 | 3 | 2 | Italy | Michele Lamberti (54.12) Ludovico Viberti (59.63) Giulia D'Innocenzo (59.45) Chiara Tarantino (54.45) | 3:47.65 | Q |
| 9 | 3 | 3 | Canada | Blake Tierney (54.12) James Dergousoff (1:01.46) Katerine Savard (58.70) Taylor Ruck (53.71) | 3:47.99 | |
| 10 | 4 | 9 | South Africa | Pieter Coetze (53.95) Lara van Niekerk (1:07.23) Erin Gallagher (57.46) Clayton Jimmie (49.39) | 3:48.03 | |
| 11 | 4 | 4 | China | Chen Jie (1:02.38) Dong Zhihao (59.18) Yu Yiting (58.27) Ji Xinjie (48.33) | 3:48.16 | |
| 12 | 3 | 7 | Spain | Carmen Weiler (1:01.00) Carles Coll (1:00.56) Mario Mollá (51.98) María Daza (55.53) | 3:49.07 | |
| 13 | 4 | 8 | Hungary | Ádám Jászó (54.23) Eszter Békési (1:08.99) Richárd Márton (52.69) Petra Senánszky (54.49) | 3:50.40 | |
| 14 | 4 | 1 | Singapore | Levenia Sim (1:02.89) Letitia Sim (1:06.94) Tzen Wei Teong (52.26) Mikkel Lee (48.93) | 3:51.02 | |
| 15 | 2 | 5 | Lithuania | Erikas Grigaitis (55.49) Rūta Meilutytė (1:07.39) Andrius Ŝidlauskas (53.67) Smilte Plytnykaitė (55.44) | 3:51.99 | |
| 16 | 4 | 0 | Philippines | Jerard Jacinto (57.38) Thanya Dela Cruz (1:08.87) Jarod Hatch (53.35) Kayla Sanchez (54.31) | 3:53.91 | |
| 17 | 3 | 1 | Kazakhstan | Xeniya Ignatova (1:02.36) Arsen Korzhakhmetov (1:03.32) Sofia Spodarenko (59.51) Adilbek Mussin (49.26) | 3:54.45 | |
| 18 | 3 | 9 | Slovakia | Teresa Ivan (1:02.55) František Jablčník (1:04.84) Tibor Tišťan (54.88) Tamara Potocká (55.57) | 3:57.84 | |
| 19 | 3 | 8 | Hong Kong | Cindy Cheung (1:02.18) Lau Shiu Yue (1:10.14) Natalie Kan (1:00.00) Ian Ho (50.77) | 4:03.09 | |
| 20 | 2 | 2 | Mongolia | Ariuntamir Enkh-Amgalan (1:04.72) Erkhes Enkhtur (1:05.48) Enkhtamir Batbayar (58.42) Batbayaryn Enkhkhüslen (56.47) | 4:05.09 | NR |
| 21 | 2 | 8 | India | Suvana Chetana Baskar (1:06.32) Likhith Selvaraj Prema (1:03.53) Tanish George Mathew (56.04) Dhinidhi Desinghu (59.21) | 4:05.10 | |
| 22 | 1 | 6 | Cook Islands | Jacob Story (59.91) Lanihei Connolly (1:10.66) Wesley Roberts (54.69) Mia Laban (1:00.54) | 4:05.80 | |
| 23 | 3 | 0 | Thailand | Ratthawit Thammananthachote (58.10) Saovanee Boonamphai (1:11.32) Navaphat Wongcharoen (53.71) Jenjira Srisaard (1:02.81) | 4:05.94 | |
| 24 | 2 | 3 | Bahamas | Lamar Taylor (56.82) Rhanishka Gibbs (1:12.42) Marvin Johnson (56.94) Victoria Russell (1:00.73) | 4:06.91 | |
| 25 | 2 | 6 | Armenia | Artur Barseghyan (1:00.88) Ashot Chakhoyan (1:05.44) Varsenik Manucharyan (1:03.62) Ani Poghosyan (58.65) | 4:08.59 | NR |
| 26 | 2 | 0 | Uganda | Kirabo Namutebi (1:12.34) Tendo Mukalazi (1:07.69) Jesse Ssengonzi (53.76) Gloria Muzito (56.15) | 4:09.94 | NR |
| 27 | 1 | 3 | Kenya | Imara Thorpe (1:09.59) Maria Brunlehner (1:14.09) Ridhwan Mohamed (57.84) Monyo Maina (52.29) | 4:13.81 | |
| 28 | 2 | 4 | Dominican Republic | Anthony Pineiro (57.62) Javier Núñez (1:07.44) María Alejandra Fernández (1:06.43) Alejandra Santana (1:02.95) | 4:14.44 | |
| 29 | 2 | 7 | Bahrain | Amani Al-Obaidli (1:06.02) Saud Ghali (1:07.15) Ahmed Theibich (1:02.54) Noor Yusuf Abdulla (1:04.97) | 4:20.68 | NR |
| 30 | 2 | 9 | Micronesia | Katerson Moya (1:07.31) Tasi Limtiaco (1:04.60) Kestra Kihleng (1:11.67) Taeyanna Adams (1:05.67) | 4:29.25 | NR |
| 31 | 1 | 4 | Guam | James Hendrix (1:04.34) Israel Poppe (1:11.84) Amaya Bollinger (1:13.33) Mia Lee (1:01.23) | 4:30.74 | NR |
| 32 | 1 | 5 | Maldives | Hamna Ahmed (1:19.87) Mubal Azzam Ibrahim (1:14.47) Mohamed Rihan Shiham (1:01.39) Aishath Ulya Shaig (1:06.10) | 4:41.83 | |
| | 2 | 1 | Czech Republic | | Did not start | Did not start |
| | 3 | 5 | Netherlands | Maaike de Waard (1:00.67) Caspar Corbeau (59.00) Nyls Korstanje (51.36) Kira Toussaint | Disqualified | Disqualified |

### Final

The final was started at 20:48.
| Rank | Lane | Nation | Swimmers | Time |
| | 3 | United States | Hunter Armstrong (53.07) Nic Fink (58.27) Claire Curzan (56.54) Kate Douglass (52.34) | 3:40.22 |
| | 5 | Australia | Bradley Woodward (53.92) Sam Williamson (59.54) Brianna Throssell (57.22) Shayna Jack (52.44) | 3:43.12 |
| | 4 | Great Britain | Medi Harris (1:00.28) Adam Peaty (59.42) Matthew Richards (52.87) Anna Hopkin (52.52) | 3:45.09 |
| 4 | 2 | Poland | Ksawery Masiuk (53.39) Dominika Sztandera (1:06.98) Jakub Majerski (51.05) Katarzyna Wasick (54.62) | 3:46.04 |
| 5 | 6 | Greece | Apostolos Christou (53.50) Arkadios Aspougalis (1:01.22) Anna Ntountounaki (56.88) Theodora Drakou (55.09) | 3:46.69 |
| 6 | 8 | Italy | Michele Lamberti (54.48) Nicolò Martinenghi (58.21) Giulia D'Innocenzo (1:00.22) Chiara Tarantino (54.38) | 3:47.29 |
| 7 | 1 | Sweden | Hanna Rosvall (1:01.50) Erik Persson (1:00.16) Louise Hansson (57.39) Björn Seeliger (48.41) | 3:47.46 |
| 8 | 7 | Japan | Osamu Kato (54.68) Ikuru Hiroshima (1:00.50) Chiharu Iitsuka (58.16) Nagisa Ikemoto (54.26) | 3:47.60 |