Semyon Kotko (Russian: Семён Котко), Op. 81, is an opera in five acts by Sergei Prokofiev to a libretto by Sergei Prokofiev and Valentin Katayev based on Katayev's 1937 novel I, Son of Working People (Russian: Я, сын трудового народа…). It was premiered on 23 June 1940 at the Stanislavsky Opera Theatre in Moscow.

Librettist Valentin Katayev (Based on "Son of Working People" novel by Valentin Katayev)
Date of composition 1939 (Composed between summers 1938 and 1939)
Premiered 1940, June 23rd (Stanislavsky Opera Theatre) in Moscow, Russia
Dedicated to Vsevolod Meyerhold, who was at that time the director of the Stanislavsky Opera Theatre (and composer's great friend)
Type Opera
Catalogue Op. 81
Spoken language Russian
Instruments Voice (Tenor) - Semyon Kotko, a demobilized soldier who loves Sofya
4x Voice - Semyon's mother
Voice (Soprano) - Frosya, Semyon's sister who loves Mikola
Voice (Bass) - Remeniuk, chairman of the village Soviet and commander of a partisan unit
Voice (Bass) - Tkachenko, a former sergeant-major and Sofya's father
Voice (Mezzo-Soprano) - Khivrya, Tkachenko's wife
Voice (Soprano) - Sofya, Tkachenko's daughter who loves Semyon
Voice (Baritone) - Tsaryov, a sailor and one of the friends of Semyon who gets hanged by the Germans
Voice (Soprano) - Lyubka, Tsaryov's fiancée
Voice (Tenor) - Mikola, a young lad who loves Frosya
Voice (Bass) - Ivasenko, an old man and the other one of the friends of Semyon who gets hanged by the Germans
Voice (Tenor) - Workman, the former landowner in the name of Klembovsky
Chorus/Choir - German interpreter, two old men, three village women, two villagers, young man, Bandura player, two Haydamaks, peasants, partisans, Red Army soldiers, Germans, Haydamaks
Orchestra
Arrangements Sergei Prokofiev: Suite from Semyon Kotko, Op. 81 bis
Autotranslations beta Sergueï Prokofiev: Semyon Kotko, Op. 81
Sergej Sergeevič Prokof'ev: Semyon Kotko, Op. 81
Sergei Sergejewitsch Prokofjew: Semyon Kotko, Op. 81