Caio Kai Koch-Weser (born July 25, 1944 in Rolândia, Brazil) is a German economist, civil servant and business executive.

Prior to becoming Secretary of State, he served in the World Bank in a number of positions for 26 years, from 1991–1999 as Vice President and from 1996–1999 as Managing Director of Operations.

He served as Personal Assistant to the President of the Bank Robert McNamara (1977–1980), Division Chief for China (1980–1986), and Director of Western Africa Department (1986–1990).

During his career in the World Bank, he mostly lived in Washington D.C. but also worked in Asia, Latin America, Eastern Europe, the Middle East, and Africa.

After the 2005 elections and the formation of a new government under Chancellor Angela Merkel, Koch-Weser decided to leave his post at the Ministry of Finance, and was appointed to the board of Deutsche Bank, as Vice Chairman, in January 2006.