State Route 45 (SR 45) is a state highway that runs south-to-north through portions of Seminole, Miller, Early, Calhoun, Terrell, Webster, and Sumter counties in southwestern Georgia. The route runs from its southern terminus at US 84 and SR 38 in Iron City to its northern terminus at US 280 and SR 27 in Plains.

From its southern terminus at US 84/SR 38 in Iron City, SR 45 travels north to US 27/SR 1/SR 91 west of Colquitt. The four routes, concurrent, travel east to Colquitt, where SR 45 departs and continues north. After brief concurrencies with SR& 62 and SR 216 in and around Arlington, SR 45 continues to the northeast, to Morgan, where it is briefly concurrent with SR 37. The route continues north from Morgan to US 82/SR 50. The three routes are concurrent east to Dawson, where SR 45 departs and continues north, concurrent with SR 520. Just north of Dawson, SR 45 departs SR 520 and continues north to Plains, where it intersects terminates at US 280 and SR 27.

SR 45 is a rural route, and as such, sees very little traffic. The route sees an Average Annual Daily Traffic (AADT) of less than 2,000 vehicles except when concurrent with U.S. Routes 27 and 82, and SR 520. Between Morgan and Dawson, the AADT is as low as 400 vehicles.

State Route 45 Alternate (SR 45 ALT) is a short alternative route to the SR 45 mainline in downtown Arlington.

State Route 45 Connector (SR 45 CONN) is a short connector route connecting the town square in Colquitt with US 27/SR 1 to the south.