August 11 - Eastern Orthodox liturgical calendar - August 13

All fixed commemorations below are observed on August 25 by Orthodox Churches on the Old Calendar.^{[note 1]}

For August 12, Orthodox Churches on the Old Calendar commemorate the Saints listed on July 30.

• Afterfeast of the Transfiguration of Our Lord, God, and Savior Jesus Christ.^{[1][note 2]}

• Hieromartyr Alexander of Comana, Bishop of Comana (3rd century)^[1][3]
• Martyrs Pamphilus and Capito, by the sword (3rd century)^[1][4][5]
• Martyrs Anicetus and Photius, and others, of Nicomedia (288)^{[1][6][7][8][9]}
• Holy 12 soldier-martyrs of Crete, by the sword.^[10][11]
• Venerable Pallamon of Egypt (c. 323), instructor of St. Pachomius the Great.^[1][12]
• Venerable Saints Sergius and Stephen, peacefully.^[11][13]
• Venerable Castor, peacefully.^[14][15]

• Martyrs Hilaria, Digna, Euprepia, Eunomia, Quiriacus, Largio, Crescentian, Nimmia, Juliana and Companions (c. 304)^{[16][note 3][note 4]}
• Saint Euplus of Catania (304))^{[16][18][note 5]} (see also: August 11)
• Saint Gracilian and Felicissima (c. 304)^{[16][note 6][note 7]}
• Saint Cassian of Benevento, Bishop of Benevento (c. 340)^[16]
• Saint Eusebius of Milan, a Greek by birth, was Bishop of Milan in Italy for sixteen years, he opposed Eutychianism (465)^[16][17]
• Saint Herculanus of Brescia, Bishop of Brescia in Italy (c. 550)^[16][17]
• Saint Molaise of Devenish (Laisrén mac Nad Froích) (563)^[11][19]
• Saint Muredach (Murtagh, Muiredach), first Bishop of Killala and founder of Innismurray (6th century)^{[1][11][20][21]}
• Saint Seigine (Ségéne mac Fiachnaí), Abbot of Iona (652)^[1][11][22]
• Saint Porcarius, Abbot of Lérins, and 500 Companions, massacred by the Saracens (c. 732)^{[16][23][note 8]}
• Saint Jambert (Jænberht, Janbert), fourteenth Archbishop of Canterbury (792)^[11][16][24]
• Saint Merewenna (Marwenne, Morwenna), the local saint of Marhamchurch near Bude in Cornwall.^[16]
• Saint Ust (Justus). The town of St Just, a few miles from Penzance in Cornwall, is named after this hermit.^[16]

• New Hieromartyrs of David Gareja Monastery, slain by the Dagestanis (Lekians) (1851):^[1][11][25]

• Gerontius and Serapion (hieromonks); Otar (deacon); Monk-martyrs Germanus, Bessarion, and Michael, and New Martyr Symeon.

• Translation of relics of St. Eadwold of Cerne (Edwold) (c. 900), hermit of Cerne.^[11]

• Saint Photius the Martyr
• Cover from the Soiscél Molaisse
• Belogorsk St. Nicholas Monastery (Perm), in 1917