Theognostus (Феогност in Russian) (? - March 11, 1353), metropolitan of Kiev and Moscow.

Theognostus was born in Constantinople and later in his life became Peter's successor in Kiev and Vladimir. He chose Moscow as his primary place of dwelling.

His life was really that of a martyr. It was his lot to reconcile Novgorod with the Prince of Moscow in times of their mutual animosity. Theognostus managed to save all of the Russian churches' valuables and gave up all his personal property after he had refused to collect tribute from the churches in favor of the Mongols. He was tortured by the Tatars for such audacity, but never gave in. It was the Khan who finally gave up and confirmed the existing privileges of the Russian Orthodox Church. After a fire swept through Moscow, Theognostus started to restore the churches despite the fact that he had had nothing left in his possession.

In 1353, feeling that his days were numbered, Theognostus appointed Alexius (Bishop of Vladimir) his successor.

Theognostus was buried in the Cathedral of the Dormition in Moscow. He was canonized by the Russian Orthodox Church in the 19th century.