Kenneth J. Donnelly (July 15, 1950 – April 2, 2017) was a Massachusetts state senator for the Fourth Middlesex district, which included his hometown of Arlington and several other cities. He was a Democrat who served from 2009-17. Donnelly graduated from the University of Massachusetts Amherst with a BA in Labor Studies. He was a retired lieutenant with the Lexington Fire Department in Lexington, Massachusetts. On June 17, 2014, Donnelly endorsed fellow Democrat Don Berwick in the Massachusetts gubernatorial election, 2014.