State Route 135 (SR 135) is part of Maine's system of numbered state highways, located entirely within Kennebec County.

It runs from SR 132 in Monmouth passing U.S. Route 202 (US 202) in Winthrop and ending at the intersection with SR 8 and SR 11 at Belgrade.

The route is 23.4 miles (37.7 km) long.

The entire route is in Kennebec County.

This Maine road or road transport-related article is a stub.