The Massachusetts State Highway System in the U.S. Commonwealth of Massachusetts is a system of state-numbered routes assigned and marked by the highway division of the Massachusetts Department of Transportation (MassDOT). U.S. Highways and Interstate Highways are included in the system; the only overlaps are with the end-to-end U.S. Route 3 and Route 3 and the far-apart Interstate 295, shared with Rhode Island, and Route 295, shared with New York State. A state highway in Massachusetts is a road maintained by the state, which may or may not have a number. Not all numbered routes are maintained or owned by the state.

The Massachusetts Department of Transportation (MassDOT) oversees roads, public transit, aeronautics, and transportation licensing and registration in the US state of Massachusetts. It was created on November 1, 2009, by the 186th Session of the Massachusetts General Court upon enactment of the 2009 Transportation Reform Act.