| Mountain | State | Latitude | Longitude | Elevation (meters) | Elevation (feet) |
|---|
| Olienberg | Province of Northern Cape | -29 | 22.7 | 1296 | 4252 |
| Olienberg | Province of Northern Cape | -29.0833333 | 22.7 | 1311 | 4301 |
| Oliewenberg | Province of the Western Cape | -33.35 | 22.1 | 1657 | 5436 |
| Olifantsbeen | Free State | -30.15 | 27.3 | 1635 | 5364 |
| Olifantsberg | Province of the Western Cape | -34.2166667 | 21.5833333 | 228 | 748 |
| Olifantsberg | Province of the Western Cape | -33.95 | 19.05 | 716 | 2349 |
| Olifantsberg | Province of the Western Cape | -33.9833333 | 19.4333333 | 1358 | 4455 |
| Olifantsberg | Province of Northern Cape | -27.9666667 | 22.7666667 | 1425 | 4675 |
| Olifantsberg | Province of the Western Cape | -33.6 | 19.3833333 | 479 | 1572 |
| Olifantskop | Province of Eastern Cape | -33.3166667 | 25.95 | 779 | 2556 |
| Olifantskop | Province of Eastern Cape | -32.7166667 | 25.7166667 | 1032 | 3386 |
| Olivier se Kop | Province of the Western Cape | -32.15 | 19.0833333 | 751 | 2464 |
| Oliviersberg | Province of Northern Cape | -32.8833333 | 20.3666667 | 1273 | 4177 |
| Oliviersberg | Province of Northern Cape | -32.6333333 | 20.7166667 | 1563 | 5128 |
| Onderplaas se Berg | Province of Northern Cape | -31.8166667 | 20.1166667 | 1303 | 4275 |
| One Tree Hill | Mpumalanga | -25.5666667 | 31.65 | 370 | 1214 |
| One Tree Hill | Province of KwaZulu-Natal | -29.95 | 30.4166667 | 827 | 2713 |
| One Tree Hill | Province of KwaZulu-Natal | -28.95 | 29.1666667 | 1936 | 6352 |
| Ongoya | Mpumalanga | -27.15 | 30.25 | 1746 | 5728 |
| Ontongskop | Province of the Western Cape | -33.35 | 19.0833333 | 759 | 2490 |
