Anthony, John, and Eustathius (Eustathios, Eustace; Russian: Антоний, Иоанн and Евстафий, Lithuanian: Antanas, Jonas ir Eustachijus; Martyrs of Vilnius, Russian: Виленские мученики, Lithuanian: Vilniaus kankiniai) are saints and martyrs (died 1347) of the Eastern Orthodox Church.

Algirdas was wed to the Orthodox princess, Maria of Vitebsk, and the three were permitted to minister only to her and banned from proselytizing.

The youths were later arrested for preaching in public, and were ordered by Algirdas to consume meat in his presence during an Orthodox fasting period.

Their bodies were in a glass reliquary in the crypt chapel under the altar of the cathedral in the Monastery of the Holy Spirit in Vilnius, Lithuania.

Their relics, said to be incorruptible, have since been moved to the main sanctuary of the cathedral.