Akira Iriye (入江 昭, Irie Akira; October 20, 1934 – January 27, 2026) was an American historian specializing in diplomatic history, international and transnational history. He taught at University of Chicago and Harvard University until his retirement in 2005.

In 1988, Iriye served as president of the American Historical Association, the only Japanese citizen to do so, and also served as president of the Society for Historians of American Foreign Relations. In 2005, he was awarded the Order of the Sacred Treasure, Gold and Silver Star, one of Japan's highest civilian honors. He was also awarded Japan's Yoshida Shigeru Prize for best book in public history. He also served as a member of the American Academy of Arts and Sciences beginning in 1982.

Iriye was born in Tokyo on October 20, 1934, and graduated from Seikei High School. His father, Keishiro Iriye, was trained in law at Waseda University and published on matters related to Japan and international relations both as a legal scholar and journalist. Akira went to the United States to study at Haverford College, where Wallace MacCaffrey interested him in the study of English history. He graduated in 1957, and accepted an invitation from the Harvard History Department's Committee on American Far Eastern Policy Studies. Iriye finished his Ph.D. in history in 1961. At Harvard, he studied with John K. Fairbank and Ernest R. May. He was awarded a Guggenheim Fellowship in 1974.

He began as an instructor and lecturer in history at Harvard; taught at the University of California at Santa Cruz, the University of Rochester, and the University of Chicago; and accepted an appointment as professor of history at Harvard University in 1989, where he became Charles Warren Professor of American History in 1991. He was director of the Edwin O. Reischauer Institute of Japanese Studies from 1991 to 1995.

After retiring in 2005, he taught at Waseda University, Ritsumeikan University, and the University of Illinois as a guest professor.

Iriye died at a retirement home near Philadelphia, Pennsylvania, on January 27, 2026, at the age of 91.

The focus of his research and thinking first turned to the United States, China, and Japan's interactions in the period leading up to the Pacific War, a war which he experienced first hand as a child. His first book, After Imperialism: The Search for a New Order in the Far East, 1921–1931, based on his PhD thesis, made use of the multi-archival and multi-lingual research which characterizes his scholarship. The book presents the argument that the collapse of the "diplomacy of imperialism" after Treaty of Versailles left a vacuum in the East Asian international system, a theme also explored in his 1972 Pacific Estrangement: Japanese and American Expansion, 1897–1911. His 1981 Power and Culture: the Japanese-American War, 1941–1945 was a Pulitzer Prize finalist The book explained the almost instantaneous transition in 1945 from racial all-out war to alliance in terms of underlying cultural parallels between the two countries.

As a graduate student, Iriye had been supported by the Committee on American-East Asian Relations, which was initiated by the American Historical Association and organized by John Fairbank and Ernest May. Iriye then joined the new generation of scholars in the field, such as James C. Thomson, Jr. and Warren Cohen, who organized conferences to explore international relations in modern East Asia. When the Committee dissolved, he and Cohen worked to establish the Journal of American-East Asian Relations to continue its mission.