Harry Dexter White (October 29, 1892 – August 16, 1948) was an American government official in the United States Department of the Treasury. Working closely with the secretary of the treasury Henry Morgenthau Jr., he helped set American financial policy toward the Allies of World War II. He was later accused of espionage by passing information to the Soviet Union.

He was a senior American official at the 1944 Bretton Woods Conference that established the postwar economic order. He dominated the conference, and his vision of post-war financial institutions mostly prevailed over those of John Maynard Keynes, the British representative who was the other main founder. Through Bretton Woods, White was a major architect of the International Monetary Fund and World Bank.

White was accused in 1948 of spying for the Soviet Union, which he adamantly denied. He was never a Communist Party member, but he had frequent contacts with Soviet officials as part of his duties at the Treasury, passed sensitive and classified documents to people he knew were agents of the Soviet Union, and influenced policy which benefitted the Soviet Union, including maneuvering to keep tensions between Japan and the United States high. This evidence came to light prior to his death via decoded Soviet cables in the Venona Project, and later with the opening of Soviet archives in the 1990s.

Harry Dexter White was born on October 29, 1892, in Boston, Massachusetts, the seventh and youngest child of Jewish Lithuanian immigrants, Jacob Weissnovitz (or Weit) and Sarah Magilewski, who had settled in the US in the 1880s. In 1917, he enlisted in the U.S. Army, and was commissioned as a First Lieutenant and served in France as head of Company H of the 302nd Infantry until the end of World War I. Aside from one term at Massachusetts Agricultural College (1911–12), he did not begin his university studies until age 29, first at Columbia University where he studied government starting from 1922; then, after three terms there, at Stanford University, where he earned bachelor's and master's degrees in economics; and finally at Harvard University, where he taught for four years while studying for his Ph.D., which he completed in 1932 at 40 years of age. White then taught for two years at Lawrence College in Appleton, Wisconsin. His PhD dissertation won the David A. Wells Prize granted annually by the Harvard University Department of Economics. Harvard University Press published his Ph.D. thesis in 1933, as The French International Accounts, 1880–1913.

In 1934, Jacob Viner, an economist working at the Treasury Department, offered White a position at the Treasury, which he accepted. Viner would receive an honorary degree from Lawrence University, where White taught before joining the Treasury, in 1941. White became increasingly important in monetary matters, and was a top advisor to Secretary of the Treasury Henry Morgenthau Jr., especially on international financial affairs dealing with China, France, Great Britain, Japan, Latin America, and the Soviet Union. In 1938, Morgenthau created a new division—the Division of Monetary Research—and promoted White to be its director. When the United States entered World War II in 1941, Morgenthau promoted White again, naming him Assistant to the Secretary. The post of Assistant Secretary, the most senior economist position in the Treasury, finally opened up in 1945, and Morgenthau promptly nominated White to fill it. White left the Treasury in 1946 to become the U.S. Executive Director at the newly established International Monetary Fund.

In November 1941, White sent a memorandum to Morgenthau that was widely circulated and influenced State Department planning. White called for a comprehensive peaceful solution of rapidly escalating tensions between the United States and Japan, calling for major concessions on both sides. Langer and Gleason report that White's proposals were totally rewritten by the State Department and that the American key demand had been formulated long before White. It was an insistence on Japanese withdrawal from China, which Japan totally refused to consider. The complex negotiations at the top ranks of the US government, and its key allies of Britain and China, took place in late November 1941 with no further input from White or Morgenthau. White's proposals were never presented to Japan. Some historians have argued, however, that White manipulated Morgenthau and Roosevelt to provoke war with Japan in order to protect Stalin's Far Eastern front.

After the U.S. entered the war in December 1941, Secretary Morgenthau appointed White to act as liaison between the Treasury and the State Department on all matters bearing on foreign relations. He was also made responsible for the Exchange Stabilization Fund. White eventually came to be in charge of wartime international matters for the Treasury, with access to extensive confidential information about the economic situation of the US and its wartime allies. He passed numerous secret documents to men he knew were Soviet spies.

White was a dedicated internationalist, and his energies were directed at continuing the Grand Alliance with the USSR and maintaining peace through trade. He believed that powerful, multilateral institutions could avoid the mistakes of the Treaty of Versailles and prevent another worldwide depression. As head of the independently funded Office of Monetary Research, White was able to hire staff without the normal civil service regulations or background enquiries. He probably was unaware that several of his hires were spies for the USSR.