Encyclopedias, Almanacs, Transcripts, and Maps
- Ostriker, Alicia
- Ostrog
- Ostrogorski, Moses
- Ostroleka
- Ostrolenk, Bernhard
- Ostropoler, Hershele
- Ostropoler, Samson ben Pesaḥ
- Ostrow Mazowiecka
- Ostrower, Fayga
- Ostrowiec
- Ostryna
- Osvát, Ernö
- Oswald of York, St.
- Oswald, King of Northumbria, St.
- Oswiecim
- Oteiza Segura, Faustino, Bl.
- Other Adventists
- Other Adventists
- Other Bible Students
- Other Bible Students