State Route 118 is a secondary highway located in eastern Oxford County, Maine.

Its western terminus in Waterford is at State Route 35 and its eastern terminus in Norway is at the intersection of Main Street and Paris Street, where it is overlapped by State Route 117.

At the intersection of Main and Paris Streets the SR 118 designation ends.

In 1938, SR 118 was truncated to its current western terminus in Waterford, eliminating the overlaps and cutting the route's overall length by more than half.

In the 1980s, SR 118 was extended along SR 117 (its original eastern terminus) through downtown Norway to its current terminus at the junction of Main and Paris Streets, extending the designation 2.11 miles (3.40 km) to the east.