Swimming at the 2003 World Aquatics Championships – Women's 100 metre freestyle

The Women's 100m Freestyle event at the 10th FINA World Aquatics Championships swam on 24–25 July 2003 in Barcelona, Spain. Preliminary and semifinal heats were swum on July 24; the Final swam in the evening session on July 25.

Prior to the event, the World (WR) and Championship (CR) records were:
 * WR: 53.77 swum by Inge de Bruijn (Netherlands) on September 20, 2000, in Sydney, Australia
 * CR: 54.01 swum by Jingyi Le (China) on September 5, 1994, in Rome, Italy