George Bogdanovich Kistiakowsky (Russian: Георгий Богданович Кистяковский, Ukrainian: Георгій Богданович Кістяківський, romanized: Heorhii Bohdanovych Kistiakivskyi; December 1 [O.S. November 18] 1900 – December 7, 1982) was a Ukrainian-American physical chemistry professor at Harvard who participated in the Manhattan Project and later served as President Dwight D. Eisenhower's Science Advisor.

Born in Boyarka in the old Russian Empire, into "an old Ukrainian Cossack family which was part of the intellectual elite in pre-revolutionary Russia", Kistiakowsky fled his homeland during the Russian Civil War. He made his way to Germany, where he earned his PhD in physical chemistry under the supervision of Max Bodenstein at the University of Berlin. He emigrated to the United States in 1926, where he joined the faculty of Harvard University in 1930, and became a citizen in 1933.

During World War II, Kistiakowsky was the head of the National Defense Research Committee (NDRC) section responsible for the development of explosives, and the technical director of the Explosives Research Laboratory (ERL), where he oversaw the development of new explosives, including RDX and HMX. He was involved in research into the hydrodynamic theory of explosions, and the development of shaped charges. In October 1943, he was brought into the Manhattan Project as a consultant. He was soon placed in charge of X Division, which was responsible for the development of the explosive lenses necessary for an implosion-type nuclear weapon. In July 1945, he watched the first atomic explosion in the Trinity test. A few weeks later, another implosion-type weapon (Fat Man) was dropped on Nagasaki.

From 1962 to 1965, Kistiakowsky chaired the National Academy of Sciences's Committee on Science, Engineering, and Public Policy (COSEPUP), and was its vice president from 1965 to 1973. He severed his connections with the government in protest against the war in Vietnam, and became active in an antiwar organization, the Council for a Livable World, becoming its chairman in 1977.

George Bogdanovich Kistiakowsky was born in Boyarka, in the Kyiv Governorate of the Russian Empire (now part of Ukraine), on December 1 [O.S. November 18] 1900. George's grandfather Aleksandr Fedorovych Kistiakovsky was a professor of law and an attorney of the Russian Empire who specialized in criminal law. His father Bogdan Kistiakovsky was a professor of legal philosophy at the University of Kyiv, and was elected a member of the National Academy of Sciences of Ukraine in 1919. Kistiakowsky's mother was Maria Berendshtam, and he had a brother, Alexander who became an ornithologist. George's uncle Ihor Kistiakovsky was the Minister of Internal Affairs of the Ukrainian State.

Kistiakowsky attended private schools in Kyiv and Moscow until the Russian Revolution broke out in 1917. He then joined the anti-Communist White Army. In 1920 he escaped from Russia in a commandeered French ship. After spending time in Turkey and Yugoslavia, he made his way to Germany, where he enrolled at the University of Berlin later that year. In 1925, he earned his PhD in physical chemistry under the supervision of Max Bodenstein, writing his thesis on the photochemical decomposition of chlorine monoxide and ozone. He then became Bodenstein's graduate assistant. His first two published papers were elaborations of his thesis, co-written with Bodenstein.

In 1926, Kistiakowsky traveled to the United States as an International Education Board fellow. Hugh Stott Taylor, another student of Bodenstein, accepted Bodenstein's assessment of Kistiakowsky, and gave him a place at Princeton University. That year, Kistiakowsky married a Swedish Lutheran woman, Hildegard Moebius. In 1928, they had a daughter, Vera, who, in 1972 became the first woman appointed as a professor of physics at MIT. When Kistiakowsky's two-year fellowship ran out in 1927, he received a research associate and DuPont Fellowship. On October 25, 1928, he became an associate professor at Princeton. Taylor and Kistiakowsky published a series of papers together. Encouraged by Taylor, Kistiakowsky also published an American Chemical Society monograph on photochemical processes.

In 1930, Kistiakowsky joined the faculty of Harvard University, an affiliation that continued throughout his career. At Harvard, his research interests were in thermodynamics, spectroscopy, and chemical kinetics. He became increasingly involved in consulting for the government and industry. He became an associate professor again, this time at Harvard in 1933. That year he also became an American citizen and was elected to the American Academy of Arts and Sciences. In 1938, he became the Abbott and James Lawrence Professor of Chemistry. He was elected to the United States National Academy of Sciences the following year. In 1940, he was elected to the American Philosophical Society.