Stanisław Bohusz Siestrzeńcewicz (Belarusian: Станіслаў Богуш-Сестранцэвіч, 1731–1826) was a Polish Catholic clergyman who became the first bishop of the Metropolitan Archdiocese of Mohilev (Mogilev), an Archbishop from 1784 and a prominent member of the Russian Academy (1807), who had earlier converted from Calvinism.

Stanisław Bohusz Siestrzeńcewicz was born in Zanki, Troki Province (now Svislach District Grodno Region).

[2] The newly appointed bishop oversaw all Latin Church Catholics in Russia[3] (including Moscow and Saint Petersburg).

His appointment was made without the consent of Pope Pius VI,[1] and in 1783 an extraordinary ambassador of the Holy See, Giovanni Andrea Archetti, was sent to Saint Petersburg settle the conflict.

Following the talks, in exchange for certain concessions, the pope approved Siestrzeńcewicz's nomination and the post of archbishop and handed him the pallium on 22 February 1784.