| William South | |
| Occupation: | Jockey |
| Birth Date: | c. 1734 |
| Death Date: | 13 September 1791 |
| Race: | Major races Epsom Derby (1788) |
| Horses: | Sir Thomas |
William South (c. 1734 - 13 September 1791) was a Derby-winning British jockey. At the age of 54, he won the ninth running of the race on the horse Sir Thomas, trained by Frank Neale and owned by George, Prince of Wales, the future George IV.