State Route 37 is a northwest-southeast highway (signed west–east) in Ohio. Its western terminus is at State Route 12 in Findlay, and its eastern terminus is at State Route 78 near Malta.

State Route 37 is an original state highway that went from Lancaster to Marietta. In 1932, the route was extended to Findlay along its current route. In 1935, its eastern terminus was shortened to its current terminus, giving that route to State Route 78 and the now defunct State Route 77 (now part of State Route 60).