State Route 140 (SR-140) is a 12-mile-long (19 km) route in Dallas County in the U.S. state of Alabama. It begins at State Route 41 on the eastern side of Selma and ends at its junction with State Route 14 near the Autauga County line.

SR-140 begins at SR-41 in Selma. It heads to the east-southeast roughly parallel to the Alabama River. As the river curves to the north east of Selma, so too does SR-140. Near the end of the route, the river bends away to the east and SR-140 continues north. It ends at an intersection with SR-14 less than a half-mile (0.8 km) from the Autauga County line.

State Route 140 was created in 1986. It is routed along the former route of State Route 14. When a new by-pass route leading from the northeastern side of Selma towards Prattville was completed, State Route 14 was aligned along the new route, and State Route 140 was assigned to the former route of State Route 14.

The entire route is in Dallas County.