| Country: | GRC |
| Type: | EO |
| Route: | 16a |
| Direction A: | North |
| Direction B: | South |
| Terminus B: | Polygyros |
| Regions: | Central Macedonia |
Greek National Road 16a is a national highway in Chalkidiki, Central Macedonia, Greece. It connects Polygyros with Greek National Road 16 near Agios Prodromos.