Swimming at the 2023 World Aquatics Championships – Women's 400 metre individual medley

The women's 400 metre individual medley competition at the 2023 World Aquatics Championships was held on 30 July 2023.

Records
Prior to the competition, the existing world and championship records were as follows.

The following new records were set during this competition.

Heats
The heats were held at 10:32.

Final
The final was held at 21:01.