| Province: | NB |
| Type: | NB |
| Route: | 123 |
| Maint: | New Brunswick Department of Transportation |
| Length Km: | 51.98 |
| Length Ref: | [1] |
| Length Round: | 1 |
| Established: | 1976.[2] |
| Direction A: | South |
| Direction B: | North |
| Terminus A: | in Chipman |
| Cities: | Chipman, Doaktown |
| Terminus B: | in Doaktown |
| Previous Type: | NB |
| Previous Route: | 122 |
| Next Type: | NB |
| Next Route: | 124 |
Route 123 is a mostly North/South provincial highway in the Canadian province of New Brunswick. The road runs from Route 10 in Chipman. The road has a length of approximately 52 kilometres, and services small, otherwise isolated rural communities. In these areas, the highway is often unofficially referred to as "Main Street." The Highway is known as Main Street and McLeod Avenue in Chipman. The road is then known as Grand Lake Road from Gaspereau Forks to Doaktown. Lastly upon entering Doaktown, the road is named South Road.
The Grand Lake Road was upgraded and completed in the early 1970s. It, along with a former section of Route 116 between Gaspereau Forks and Chipman, became Route 123 in 1976.