UFC 73: Stacked was a mixed martial arts (MMA) event held by the Ultimate Fighting Championship (UFC). It took place on July 7, 2007 at the ARCO Arena in Sacramento, California and featured a total of nine bouts: four on the preliminary card and five on the main card. In the main event, Anderson Silva put his UFC Middleweight Championship belt on the line against Nate Marquardt. The card's other championship match had Sean Sherk defending his UFC Lightweight Championship belt against Hermes Franca.