State Route 347 (SR 347, OH 347) is an east–west state highway in central portion of the U.S. state of Ohio. The western terminus of SR 347 is at an interchange with U.S. Route 33 (US 33) just south of the unincorporated community of East Liberty. Its eastern terminus is at a T-intersection with SR 37 just 0.25 miles (0.40 km) of the village of Magnetic Springs.

Along its way, SR 347 passes through eastern Logan County and the central portion of Union County. No segment of SR 347 is inclusive within the National Highway System (NHS), a network of highways deemed most important for the country's economy, mobility and defense.

The debut of SR 347 took place in 1935. At the time, the highway was a short connector routed along its present alignment between its junction with SR 4 in the hamlet of Pharisburg and its eastern terminus at SR 37 near Magnetic Springs.

In 1937, SR 347 was extended west along its current alignment to its present western terminus near East Liberty at what would later become US 33, but at the time was known as SR 32. This extension followed a previously un-numbered road.