Konstantin Sigismundovich Zharnovetsky (Russian: Константин Сигизмундович Жарновецкий, 1881, Yerevan – 1941, Leningrad) was a Russian Bolshevik, a commissar of the Peterhof Military Revolutionary Committee, the head of the Red Army in the city of Narva, a professor heading the faculty of social studies at Leningrad University.
During 1906–1910, he was repeatedly arrested and banished from St. Petersburg; since 1910, he settled in Peterhof and taught the history of Russian literature in the gymnasium for boys named after Emperor Alexander II.
In July, 1917, he was arrested under the order of the Interim Government, but he was released due to the pressure of military committees.
From October 1917, he became the Commissioner of the Peterhof Military Revolutionary Committee, he also participated in the battles against the General Krasnov in Krasnoye Selo.
After the Brest peace, he returned to Petrograd and was appointed as the head of agitation and propaganda department of the gubernial Party Committee.