Christopher Edwin Duncan (born May 5, 1981 in Tucson, Arizona) is an outfielder/first baseman for the St. Louis Cardinals. He is the son of former Oakland Athletics catcher and current St. Louis pitching coach Dave Duncan. His older brother Shelley plays in the New York Yankees organization. His current entrance music is "Bombtrack" by Rage Against The Machine.

Duncan is a graduate of Canyon del Oro High School in the Tucson suburb of Oro Valley. He was drafted by the Cardinals in 1999 and made his debut with the big club on September 10, 2005. On October 2, 2005, he became the last player to hit a home run at Busch Memorial Stadium during the regular season.

After spending most of the first half of the 2006 season working his way into the regular roster, he has become a great find for the Cardinals. In 2006, he was third in all of baseball behind David Ortiz and Ryan Howard in homers per at bat for players with at least 75 at bats. For the season, Duncan hit 22 home runs in only 280 at bats.