Alexander Semenovich Holevo (Russian: Алекса́ндр Семéнович Хóлево,[1] also spelled as Kholevo and Cholewo) is a Soviet and Russian mathematician, one of the pioneers of quantum information science.

He graduated from Moscow Institute of Physics and Technology in 1966, defended a PhD Thesis in 1969 and a Doctor of Science Thesis in 1975.

In 1973 he obtained an upper bound for the amount of classical information that can be extracted from an ensemble of quantum states by quantum measurements (this result is known as Holevo's theorem).

A.S. Holevo developed the mathematical theory of quantum communication channels, the noncommutative theory of statistical decisions, he proved coding theorems in quantum information theory and revealed the structure of quantum Markov semigroups and measurement processes.

A.S. Holevo is the author of about one-hundred and seventy published works, including five monographs.