State Route 707 (SR 707, OH 707) is a 19.45-mile (31.30 km) long east–west state highway in the western portion of the U.S. state of Ohio. The western terminus of SR 707 is at the Indiana state line approximately 7.50 miles (12.07 km) southwest of Willshire, where it transitions into Indiana State Road 218 (IN 218). The eastern terminus of SR 707 is at SR 117 nearly 3 miles (4.8 km) north of Mendon.

The entirety of SR 707 is situated within the northern half of Mercer County. No portion of the route is included within the National Highway System (NHS). The NHS is a network of highways identified as being most important for the economy, mobility and defense of the nation.

SR 707 was established in 1937. It has maintained the same routing through the northern portion of Mercer County throughout its history.

The entire route is in Mercer County.