Greenstein (born June 7, 1950 in Brooklyn, New York) is an American Democratic Party politician who represents the 14th legislative district in the New Jersey Senate.
She is the first woman to hold the Mercer-Middlesex regional State Senate district since Anne Clark Martindell, who filled the seat from 1974 to 1977.
She previously served in the General Assembly from 2000 to 2010.