| Abbreviation | Definition |
|---|---|
| OBCF | Overseas Burmese Christian Fellowship |
| OBCM | Office of Black Catholic Ministries |
| OBCS | Olive Branch Christian School |
| OBE | Over By Epiphany |
| OBF | Ohio Bible Fellowship |
| OBF | Oxford Bible Fellowship |
| OBHC | Oklahoma Baptist Homes for Children |
| OBL | Oblate |
| OBP | Original Bible Project |
| OBSC | Ohio Baptist State Convention |
| OBT | Orange Bitey Thing |
| OC | Old Covenant |
| OC | Operation Christ |
| OC | Other Caste |
| OC | Overtly Christian |
| OCA | Oklahoma Christian Academy |
| OCB | Orange Catholic Bible |
| OCBC | Orange County Buddhist Church |
| OCC | Orange County Canaanites |
| OCC | Oswaldtwisle Community Church |