Swimming at the 2018 Summer Youth Olympics – Girls' 4 × 100 metre medley relay
The girls' 4 × 100 metre medley relay event at the 2018 Summer Youth Olympics took place on 8 October at the Natatorium in Buenos Aires, Argentina.
Results
Final
The final was held at 19:29.| Rank | Lane | Name | Nationality | Time | Notes |
| 4 | Peng Xuwei Zheng Muyan Lin Xintong Yang Junxuan | 4:05.18 | |||
| 5 | Kaylee McKeown Chelsea Hodges Michaela Ryan Abbey Webb | 4:05.46 | |||
| 7 | Daria Vaskina Anastasia Makarova Polina Egorova Elizaveta Klevanovich | 4:06.07 | |||
| 4 | 1 | Fernanda de Goeij Ana Vieira Maria Pessanha Rafaela Raurich | 4:10.93 | ||
| 5 | 3 | Ryan White Kate Douglass Kaitlynn Sims Maddie Donohoe | 4:16.79 | ||
| 6 | 6 | Mariella Venter Christin Mundell Duné Coetzee Kate Beavon | 4:17.78 | ||
| 2 | Madison Broad Nina Kucheran Avery Wiseman Kyla Leibel |