January 20 in Eastern Orthodox liturgical calendars is a feast day and a day of commemoration of saints and martyrs. Although some Orthodox churches use the Revised Julian Calendar and others use the traditional Julian calendar, the fixed commemorations for their respective January 20 are broadly the same, no matter which calendar is used.
Martyrs Inna, Pinna, and Rimma (1st-2nd century), disciples of the Apostle Andrew in Scythia
Martyrs Bassus, Eusebius, Eutychius, and Basilides, at Nicomedia (303)
Venerable Euthymius the Great (473)
Saint Leo I, Eastern Roman Emperor and Confessor (474)
Martyrs Thyrsus and Agnes (5th century)
Saint Peter the Publican (Tax Collector, Customs Inspector) of Constantinople (c. 527-565)
Saint Fabian, Pope of Rome (250)
Saint Sebastian, one of the most renowned of all the martyrs of Rome (c. 288)
Saint Molagga (Molacus, Laicin), disciple of Saint David in Wales, founded a monastery in Fulachmhin (Fermoy), Ireland (655)
Saint Féchín (Fechinus), founded Fore Abbey at Meath (665)
Saint Maurus, monk and Abbot of Classe in Ravenna (Basilica of Sant'Apollinare in Classe), and finally Bishop of Cesena (946)
Venerable Laurence the Recluse of the Kiev Caves (13th-14th century)
Venerable Euthymius the Silent, Schemamonk of the Kiev Caves (14th century)
Saint Neophytus of Vatopedi, Mount Athos (14th century) (see also: January 21)
Saint Euthymius, Patriarch of Tarnovo (Turnovo, Trnovo) and Bulgaria (1402)
Saint Euthymius of Syamzha (Syadem, Syandema, Syandemsk, Syandemsky, Syanzhema, Syanzhemsk), Vologda Oblast (1470)
Venerable Euthymius of Arkhangelsk (1523)