Alexey Andreyevich Lyapunov (8 October 1911 – 23 June 1973) was born in Moscow, Russian Empire, and died in Moscow, Soviet Union. He was a Soviet mathematician, an early pioneer of computer science, and one of the founders of Soviet cybernetics. Lyapunov was educated at Moscow State University under the guidance of Nikolai Luzin and Pyotr Novikov. Over his career, he was affiliated with the Steklov Mathematical Institute, the Sobolev Institute of Mathematics, and Novosibirsk State University.

A member of the Academy of Sciences of the Soviet Union, Lyapunov was a specialist in the fields of real function theory, mathematical problems of cybernetics, set theory, programming theory, mathematical linguistics, and mathematical biology. His notable students included Andrey Yershov, Sergey Yablonsky, Rafail Krichevskii, Oleg Lupanov, and Yuri Zhuravlyov. His recognitions include the Order of Lenin and the Computer Pioneer Award.

Composer Sergei Lyapunov, mathematician Aleksandr Lyapunov, and philologist Boris Lyapunov were close relatives of his. In 1928, Lyapunov enrolled at Moscow State University to study mathematics, becoming a student of Nikolai Luzin in 1932. Under Luzin's mentorship, Lyapunov began his research in descriptive set theory. He achieved worldwide renown for his theorem on the range of an atomless vector-measure in finite dimensions, which is now known as the Lyapunov Convexity Theorem.

Lyapunov was on the staff of the Steklov Institute of Mathematics from 1934 until the early 1950s. When Mstislav Keldysh organized the Department of Applied Mathematics (now the M.V. Keldysh Institute of Applied Mathematics), he proposed that Lyapunov lead its work on programming. In 1954, A.A. Lyapunov was invited by Anatoly Kitov, the scientific director of Computing Center No. 1 of the USSR Ministry of Defense, to join the center as head of the laboratory. Lyapunov worked at this military computing center until 1960.

In 1961, Lyapunov moved to the Institute of Mathematics of the Siberian Division of the Academy of Sciences of the Soviet Union (now the Sobolev Institute of Mathematics), where he founded the department of cybernetics. At Novosibirsk State University, he established the Department of Theoretical Cybernetics as well as the Laboratory of Cybernetics at the Institute of Hydrodynamics of the Siberian Division of the Academy of Sciences of the Soviet Union (now the Lavrentiev Institute of Hydrodynamics), leading the laboratory until the end of his life. In 1964, Lyapunov was elected a member of the Academy of Sciences of the Soviet Union and joined its Division of Mathematics. He received several state honors, including the Order of the Red Star in 1944, the Order of the Badge of Honour in 1953, two Orders of the Red Banner of Labour in 1956 and 1967, and the Order of Lenin in 1971. In 1996, he was posthumously awarded the IEEE Computer Society's Computer Pioneer Award.

Reference materials include a biography of Lyapunov and accounts of his contributions to cybernetics. Additional references commemorate Lyapunov's 90th birthday and document Lyapunov at IPM RAS.