| Species name | Common name | Distribution | Max. Length (cm) |
|---|---|---|---|
| Williamia gussonii (Costa, 1829) |
Mediterranean Sea | 0.7 | |
| Williamia krebsii (Morch, 1877) |
Western Atlantic | ||
| Williamia magellanica Dall, 1927 |
Western Atlantic | 0.4 | |
| Williamia peltoides (Carpenter, 1864) |
Shield false limpet | Eastern Pacific | |
| Williamia radiata (Pease, 1861) |
Pacific Ocean |