State Route 45 is a west–east route in Davidson County, Tennessee. It connects US-431 (Whites Creek Pike) in northwest Nashville with I-40 east of the city.

State Route 45 makes up much of the northern half of Nashville's Old Hickory Boulevard loop. It continues the loop from the intersection with Whites Creek Pike. Traveling parallel to Little Creek, it continues past I-24 Exit 40 to its intersection with US-31W/US-41 (Dickerson Pike). After that intersection, the road becomes a four-lane divided highway. SR-45 goes south of Cedar Hill Park and past I-65 Exit 92 to enter Madison. After it crosses the Cumberland River, SR-45 continues onto Robinson Road through the towns of Old Hickory and Lakewood. In Lakewood, SR-45 rejoins Old Hickory Boulevard and heads south, by The Hermitage, to the eponymous town of Hermitage. SR-45 ends at I-40 Exit 221, and Old Hickory Boulevard continues south to Bell Road.

The entire route is in Davidson County.