Route 105 is a 29.36-mile-long (47.25 km) state highway in southeastern Massachusetts, running from Marion to Halifax in a generally north–south direction.

The highway winds in a westerly direction through Rochester.

When the highway enters Long Plain village in Acushnet, the only town in Bristol County on the route, Route 105 turns in a northerly direction.

Route 105 then shoots off in a northeasterly direction into Middleborough through the town's center and, after its intersection with U.S. Route 44, turns in a northerly direction through East Middleborough, going past Oak Point along the way.

The highway ends at Route 106 in Halifax west of the town's center.