| Named By: | Watson in 1909 |
| Time Period: | Early Jurassic |
| Location: | England |
| Size: | Unavailable |
| Diet: | Piscivore |
| Fossil(s): | At least one almost complete specimen |
| Classification: | | Chordata | Reptilia | Sauropterygia | Plesisauria | Plesiosauridea | |
| Also known as: | | Plesiosaurus homalospondylus | Plesiosaurus macropterus | |
Microcleidus is an extinct genus of sauropterygian reptile belonging to the plesiosauroidea suborder. It was about the size of a medium-sized dolphin, reaching a length of 3 metres (9.8 ft). The species has 40 neck vertebrae and a short tail of 28 vertebrae.