Encyclopedias, Almanacs, Transcripts, and Maps
- Orona Madrigal, Justino, St.
- Orosius, Paulus°
- Orot
- Orozco y Jiménez, Francisco
- Orozco, Alfonso de, Bl.
- Orpah
- Orpaz Averbuch, Yitzhak
- Orphan (in the Early Church)
- Orphan, Orphanage
- Orsha
- Orshanski, Ilya (Elijah) Grigoryevich
- Orsi, Giuseppe Agostino
- Orsova
- Ort
- Orta, Garcia de
- Orten, Jiří
- Ortenberg, Arthur (1926– ) and Claiborne, Liz
- Orthodox and Oriental Orthodox Churches
- Orthodox Church in America (OCA)
- Orthodox Church of Bulgaria