James Addison Baker, III (born April 28, 1930) is an American attorney, politician, political administrator, and political advisor.

He served as the Chief of Staff in President Ronald Reagan's first administration and in the final year of the administration of President George H. W. Bush. Baker also served as Secretary of the Treasury from 1985-1988 in the second Reagan administration, and Secretary of State in the George H. W. Bush administration. He is also the namesake of the James A. Baker III Institute for Public Policy at Rice University in Houston, Texas.

James Addison Baker was born in Houston, Texas at 1216 Bissonnet, to James Addison Baker Jr. (1892–1973) and Ethel Bonner (born Means) Baker (August 6, 1894–April 26, 1991). His father was a partner of Houston law firm Baker Botts. Baker has a sister, Bonner Baker Moffitt.