Chad Michael Qualls (born August 17, 1978, in Lomita, California) is a relief pitcher for the Arizona Diamondbacks.

Qualls allowed two grand slams to the Chicago White Sox which were eerily similar. In the 2005 World Series, when Qualls pitched for the Houston Astros, Qualls gave up a grand slam on his first pitch in the 7th inning to Paul Konerko to give the Sox the lead during Game 2. On June 24, 2006, when the Astros and Sox met up in an interleague rematch of the previous year's World Series, Qualls served up a grand slam on his first pitch in the 7th inning to third baseman Joe Crede to tie the game. Both grand slams were hit at U.S. Cellular Field into the left field stands.

On December 14, 2007, Qualls was dealt to the Arizona Diamondbacks along with Chris Burke and Juan Gutierrez for Jose Valverde.