Route 135 is a 29.53-mile-long (47.52 km) east-west state highway in eastern Massachusetts.

The first 13 miles (21 km) of the Boston Marathon, from Hopkinton to Wellesley, follow Route 135.

The route enters Hopkinton, and turns northeast at an intersection with West Main Street, which provides nearby access to I-495.

The highway enters Needham, and splits off Great Plain Avenue towards Dedham.

Route 135 traveled west and south on Highland Avenue into downtown Needham, then west onto Great Plain Avenue and its current routing.