Biltong and beef jerky are both dried beef products. The main difference between them is the way they’re dried. All kinds of jerky, including beef jerky, involve thin cuts of meat, normally pre-marinated, being cooked on a rack, normally at a low temperature. This process slowly dehydrates and cooks the meat, with the end-product being a tougher, smokier,  palatably chewy strip. 

Biltong, on the other hand, is typically cured and marinated for a day before the drying process, which involves having the meat up to air dry for a week, before further drying, and slicing to size.  Biltong tends to have a more gamey taste than jerky and is generally slightly more tender.