| Mountain | State | Latitude | Longitude | Elevation (meters) | Elevation (feet) |
|---|
| Oogkop | Province of Northern Cape | -27.5 | 23.45 | 1367 | 4485 |
| Oorlogspoortberge | Province of Eastern Cape | -32.3833333 | 23.4666667 | 1080 | 3543 |
| Oorsprongkop | Mpumalanga | -25.4166667 | 31.7666667 | 256 | 840 |
| Opisweni | Province of KwaZulu-Natal | -28.8333333 | 30.7333333 | 1049 | 3442 |
| Oppermanskop | Province of Northern Cape | -31.1333333 | 25.0333333 | 1797 | 5896 |
| Oqaqeni | Province of KwaZulu-Natal | -29.5333333 | 30.7166667 | 496 | 1627 |
| Osberg | Province of the Western Cape | -33.4 | 21.6833333 | 1407 | 4616 |
| Osberg | Province of Eastern Cape | -32.0666667 | 24.7666667 | 1660 | 5446 |
| Osberg | Province of the Western Cape | -32.1666667 | 19.2833333 | 919 | 3015 |
| Osberg | Province of Eastern Cape | -33.35 | 25.3166667 | 350 | 1148 |
| Osberg | Province of Northern Cape | -31.1833333 | 23.9166667 | 1620 | 5315 |
| Osberg | Province of Eastern Cape | -33.6166667 | 24.3333333 | 683 | 2241 |
| Oshoek se Berg | Province of the Western Cape | -33.5166667 | 20.8166667 | 682 | 2238 |
| Oshoekberg | Province of the Western Cape | -32.1 | 22.7 | 1650 | 5413 |
| Oskarberg | Province of KwaZulu-Natal | -28.35 | 30.5333333 | 1101 | 3612 |
| Oskop | Free State | -29.5833333 | 25.4166667 | 1271 | 4170 |
| Oskop | Province of Eastern Cape | -32.4 | 26.0833333 | 1270 | 4167 |
| Osplaat se Berg | Province of Northern Cape | -30.0833333 | 17.9833333 | 1342 | 4403 |
| Osseberg | Province of Northern Cape | -30.1166667 | 17.75 | 694 | 2277 |
| Ossewakop | Province of KwaZulu-Natal | -27.3833333 | 30.15 | 1926 | 6319 |
