| Named By: | unavailable |
| Time Period: | Middle Devonian, 390 Ma |
| Location: | Germany - Klerf Formation |
| Size: | Estimated about 2.5 meters long from the head to the tip of the telson (end of the tail) |
| Diet: | Carnivore |
| Fossil(s): | Single chelicerae |
| Classification: | | Arthropoda | Merostomata | Eurypterida | Pterygotidae | |
Jaekelopterus ("Otto Jaekel's wing") is an extinct genus of Eurypterida. Jaekelopterus lived approximately 390 million years ago. At an estimated length of 2.5 metres (8.2 ft), it is the largest known arthropod ever discovered, surpassing Pterygotus and even the millipede-like Arthropleura. There are two species, one being the type species, J. rhenaniae, from freshwater strata in the Rhineland, and J. howelli from estuarine strata in Wyoming.