State Route 120 is a short route in Tallapoosa County in the east-central part of the state. The western terminus of the route is at its junction with State Route 49 at the unincorporated community of Reeltown. The eastern terminus of the route is at its junction with State Route 14 west of Notasulga.

State Route 120 is four miles (6 km) long. It travels in a general southeastward direction and is routed along a two-lane road. It serves as connector between State Route 14 as it leads westward from Auburn and northbound State Route 49 as it leads towards Lake Martin.

The entire route is in Tallapoosa County.