The year 2003 was the 3rd year in the history of World Extreme Cagefighting, a mixed martial arts promotion based in the United States.

In 2003 WEC held 3 events beginning with, WEC 6: Return of a Legend.

WEC 6: Return of a Legend[1] was an event held on March 27, 2003 at the Tachi Palace in Lemoore, California, United States.

WEC 7: This Time It's Personal[2] was an event held on August 9, 2003 at the Tachi Palace in Lemoore, California, United States.

WEC 8: Halloween Fury 2[3] was an event held on October 17, 2003 at the Tachi Palace in Lemoore, California, United States.