Leontiy Ivanovich Sivtsov (Russian: Леонтий Иванович Сивцов; 1872–1919) was a church reader who lived in Unalaska. Along with Aleksey Yachmenev, who like Sivtsov was Aleut himself, Sivtsov accompanied Waldemar Jochelson on his 1909–1910 ethnological studies on the Aleut.