| Named By: | Bertelli et al. in 2007 |
| Time Period: | Miocene, 15 Ma |
| Location: | Argentina |
| Size: | Between 2.28 and 3 meters tall. Skull is 71 centimetres long (45.7 centimetres of which is beak) |
| Diet: | Carnivore |
| Fossil(s): | Almost complete skull with tarsometatarsus (foot bone adapted to extend the length of the lower leg) and toe bone |
| Classification: | | Chordata | Aves | Cariamae | Phorusrhacidae | Phorusrhacinae | |
Kelenken guillermoi was a species of giant flightless predatory birds of the extinct family Phorusrhacidae, or "terror birds".