Geoffrey William Seiji Okamoto (born January 18, 1985) is an American economist and government official who served as first deputy managing director of the International Monetary Fund. Okamoto previously served as the acting assistant secretary for international finance and development in the United States Department of the Treasury. He was nominated for this position on January 1, 2019, by the White House and was never confirmed by the United States Congress. He previously served as acting assistant secretary for international markets and investment, for which he was also not confirmed.