State Route 588 (SR 588, OH 588) is an east–west state highway in the southeastern portion of the U.S. state of Ohio. The western terminus of State Route 588 is at State Route 325 in Rio Grande. Its eastern terminus is at a signalized intersection with State Route 7 in downtown Gallipolis.

State Route 588 runs entirely within the central part of Gallia County. No portion of State Route 588 is included as a part of the National Highway System, a system of highways that are considered most important for the economy, mobility and defense of the country.

State Route 588 made its debut in 1947. It was originally routed along its present alignment between the Jackson Pike (County Road 35) Y-intersection southeast of Rio Grande and its current eastern terminus at State Route 7 in Gallipolis. At that time, the combination of present State Route 588 northwest of what was its western terminus at the time and Jackson Pike southeast of that point were a part of U.S. Route 35. When the entirety of the U.S. Route 35 freeway was completed through Gallia County in 1995, State Route 588 was extended northwest from its previous western terminus along the former routing of U.S. Route 35 to its current western terminus at State Route 325 in Rio Grande.

The entire route is in Gallia County.