Robert Davis McCallum Jr. (born January 30, 1946) is an American lawyer and diplomat who served in the Bush administration. He was the Associate Attorney General of the United States from 2003 to 2006, also acting as the Deputy Attorney General from 2005 to 2006. He was appointed as the United States Ambassador to Australia in 2006, a capacity in which he served until the end of Bush's term in 2009.