| Named By: | Charles Walcott in 1911 |
| Time Period: | Middle Cambrian |
| Location: | Canada, British Columbia - Burgess Shale |
| Size: | Around 38 millimetres long |
| Diet: | Uncertain |
| Fossil(s): | Many individuals |
| Classification: | | Chordata | Cephalochordata | |
Pikaia gracilens is an extinct cephalochordate animal known from the Middle Cambrian Burgess Shale of British Columbia. Sixteen specimens are known from the Greater Phyllopod bed, where they comprised 0.03% of the community. It resembled the lancelet and perhaps swam much like an eel.