Swimming at the 2007 World Aquatics Championships – Women's 400 metre freestyle

The women's 400 metre freestyle at the 2007 World Aquatics Championships took place on 25 March (preliminaries and finals) at Rod Laver Arena in Melbourne, Australia.

The existing records at the start of the event were:
 * World record (WR): 4:02.13, Laure Manaudou (France), 6 August 2006 in Budapest, Hungary
 * Championship record (CR): 4:06.28, Tracey Wickham (Australia), at West Berlin 1978 (24 August 1978)