Ohio State Route 507 (OH 507) is a short east–west state route in western Ohio, located entirely in the northern portion of Champaign County. The western terminus of OH 507 is at US 68 1-mile (1.6 km) south of West Liberty. Its eastern terminus is at OH 245 near the Ohio Caverns approximately 4 miles (6.4 km) southeast of West Liberty.

A T-intersection with US 68 in Salem Township located approximately 0.5-mile (0.80 km) south of the boundary between Champaign County and Logan County, and 1-mile (1.6 km) south of West Liberty, marks the starting point of OH 507. Heading east from there, this state route jogs northeasterly briefly before continuing easterly through farm country. Passing its intersection with McClain Road, OH 507 turns to the southeast. At Champaign County Road 223, OH 507 bends to the northeast, and continues in that direction through its junction with OH 245 near the Ohio Caverns, where the highway comes to an end. The roadway continuing beyond OH 245 after OH 507 terminates is Mount Tabor Road.

OH 507 was first designated in 1937 along the routing that it currently occupies. Little has changed along OH 507 over the years, other than that route that it meets at its eastern terminus was designated as OH 275 when OH 507 first came into being. Later on, OH 275 would be re-designated as OH 245.

The entire route is in Salem Township, Champaign County.