| State: | NH |
| Type: | NH |
| Route: | 45 |
| Map Custom: | yes |
| Map Alt: | Map of New Hampshire Route 45 |
| Map Notes: | Map of Hillsborough County in southern New Hampshire with NH 45 highlighted in red |
| Length Mi: | 5.981 |
| Direction A: | South |
| Terminus A: | in Greenville |
| Direction B: | North |
| Terminus B: | in Temple |
| Counties: | Hillsborough |
| Previous Type: | NH |
| Previous Route: | 43 |
| Next Type: | NH |
| Next Route: | 47 |
New Hampshire Route 45 is a 5.981adj=midNaNadj=mid north–south state highway in southern New Hampshire. It runs from Greenville to Temple.
NH 45 begins at NH 123 in Greenville. It runs northwest into the town of New Ipswich for a short distance, then into the town of Temple where it ends at NH 101.
In Temple, the highway is named Senator Tobey Highway. In Greenville, the road starts as Main Street at the center of town. At the north end of town, the road becomes Temple Road then becomes Greenville-Temple Highway farther north. There are various views along the road to the nearby Wapack Range.