Rolf Parker Griffith, Jr., M.D. (born August 6, 1942) is an American retired radiation oncology physician, mathematics teacher, Army Reserve officer, entrepreneur and politician who served in the Alabama State Senate from 2006 to 2008 and then as the U.S. Representative for Alabama's 5th congressional district from 2009 to 2011. A lifelong member of the Democratic Party, while serving in Congress, at the urging of Republicans he switched parties on December 22, 2009.