WEC 31: Faber vs. Curran was a mixed martial arts (MMA) event held by World Extreme Cagefighting (WEC). The event took place on Wednesday, December 12, 2007 at the Hard Rock Hotel and Casino in Las Vegas, Nevada and was aired live on the Versus Network. The main event featured a featherweight title match between champion Urijah Faber and challenger Jeff Curran. The card also featured Doug Marshall defending his light heavyweight championship against Ariel Gandulla and Paulo Filho defending his middleweight championship against Chael Sonnen. The event drew an estimated 629,000 viewers on Versus.