| Country: | SVN |
| Type: | A |
| Route: | 3 |
| Map: | Slovenia - A3.svg |
| Length Km: | 11.3 |
| Terminus A: | A1 near Gabrk |
| Terminus B: | Fernetiči RA14 border with |
| Regions: | Littoral |
| Cities: | Sežana |
The A3 motorway (Slovenian: avtocesta A3, Karst Highway) of Slovenia is 11.3 km long. It begins at the Gabrk interchange on the A1 motorway near Divača and ends at the Italian border at Sežana, continuing on in Italy as the RA14. It connects Ljubljana with Trieste.