Ohio State Route 718 (OH 718) is a state route in western Ohio. All of OH 718 is situated within western Miami County. The western terminus of OH 718 is at OH 721 west of Pleasant Hill, and its eastern terminus is at OH 55 in Troy, near the OH 55 interchange off of I-75.

OH 718 begins at an intersection with OH 721 and Miami County Road 74 in an area west of Pleasant Hill. The route heads eastward, passing homes and fields for a stretch. The terrain in this area is flat with little changes in elevation. OH 718 continues on, intersecting with County Road 69 and County Road 9. The route crosses the Stillwater River, and enters the town of Pleasant Hill. OH 718 passes Pleasant Hill Cemetery and intersects with local roads in Pleasant Hill, until an intersection with OH 48.

The route turns to the southeast as it leaves Pleasant Hill. The road is mainly rural fields for the next several miles, turning to the southeast once more as it nears Troy. OH 718 enters Troy soon after, crossing over I-75, and terminating at an intersection with OH 55.

OH 718 was assigned to its current routing in 1937. No significant changes have taken place to OH 718 since its inception.

The entire route is in Miami County.