Alexei Sergeyevich Semyonov, born on August 12, 1950, in Moscow, is a Russian and Soviet organist, harpsichordist, and teacher. He was named Honored Artist of the Russian Federation in 2002.
In 1968 he graduated from the Gnessin Moscow Special Secondary Music School, where he studied in the class of A. P. Kantor. He then graduated from the Moscow Conservatory in 1973, studying piano with M. A. Fyodorova and organ with L. I. Roizman, and in 1975 completed postgraduate assistant training in organ and harpsichord. In 1986–1987 he continued his training at the Vienna Higher School of Music with Professor H. Haselbock and also attended the classes of N. Harnoncourt, G. Tacchetti, G. Murray, H. Vasquez, and R. Clemencic.
He began his concert career in 1972 as a solo organist and harpsichordist. From 1979 to 1993 he was a soloist of the ensemble Madrigal, where he also played the recorder, crumhorn, and other early musical instruments. He toured widely in many cities of the Soviet Union and abroad, including Austria, Germany, Italy, the Netherlands, Belgium, and Switzerland, and performed with leading choral and orchestral ensembles as well as distinguished solo musicians.
In 1988 Semyonov took part in the 22nd International Organ Festival in Mexico. In 1990 he founded the early music ensemble Lad, of which he became artistic director. The ensemble later became a prizewinner at the 8th International Van Wassenaer Competition for Authentic Ensembles in Amsterdam in 1994.
Alongside his performing career, Semyonov was active as a teacher. From 1972 to 1975, while still a student at the Moscow Conservatory, he taught organ at the Novosibirsk Conservatory. From 1975 to 1982 he taught piano at the Moscow State Pedagogical Institute named after V. I. Lenin. Since 1993 he has been a soloist of the Moscow Philharmonic, and from 2002 he has served as an associate professor in the organ and harpsichord department of the Moscow Conservatory.