State Route 123 or SR-123 is a 45.750-mile (73.627 km) state highway that serves Dale, Houston and Geneva Counties as a connection between Ariton, Ozark and Hartford. SR-123 intersects SR-167 at its southern terminus and US-231 at its northern terminus.

State Route 123 begins at its intersection with SR-167 just south of Hartford. From this point, the route travels in northerly direction where it intersects SR-52 in the central business district of Hartford. From Hartford, SR-123 travels in a northeasterly direction before turning to the north upon entering Houston County and intersecting SR-103. The route continues through its intersection with US-84 and continues in its northerly course into Dale County after crossing the Little Choctawhatchee River. SR-123 continues along its northerly course in Dale County where it intersects SR-134 and runs concurrent with it for approximately 2.5 miles (4.0 km) through the town of Newton. From the end of this concurrency through Ozark, SR-123 continues generally in this northern course in passing both Fort Rucker and Blackwell Field. Upon leaving Ozark, the route continues in a northwesterly course in route to Ariton where it then turns in a westerly direction where it meets its northern terminus with US-231.