"Father Sergius" (Russian: Отец Сергий, romanized: Otets Sergiy) is a short story written by Leo Tolstoy between 1890 and 1898 and first published (posthumously) in 1911.

He discovers on the eve of his wedding that his fiancée Countess Mary Korotkova has had an affair with his beloved Tsar Nicholas I.

The morning after, he leaves the monastery and seeks out Pashenka (Praskovya Mikhaylovna), whom he, with a group of other boys, had tormented many years ago.

He begins to wander, until eight months later he is arrested in the company of a blind beggar who makes him feel closer to God.

Tolstoy's story is based on hagiography about the probably sixth-century Palestinian hermit Jacob the Monk, who was revered in Russian Orthodox Christianity.