| Country: | JPN |
| Type: | National |
| Route: | 303 |
| Map Custom: | yes |
| Length Km: | 126.2 |
| Length Ref: | [1] |
| Established: | 1970 |
| Terminus A: | Gifu |
| Previous Type: | Route |
| Previous Route: | 302 |
| Next Type: | Route |
| Next Route: | 304 |
National Route 303 is a national highway of Japan connecting Gifu, Gifu and Wakasa, Fukui in Japan. The highway has a total length of 122.8km (76.3miles).
An incident occurred on 14 November 2018, when the Japan Ground Self-Defense Force was conducting a military exercise in Takashima, Shiga near Route 303. During the exercise, the JGSDF unintentionally hit the road with a live 81 mm mortar round. The resultant explosion caused fragments of pavement go flying, some of which struck a parked car with an elderly man inside. The man was not injured, but the car was damaged, with dents and some shattered windows.[2]