How Massachusetts's Primary Election Works

Massachusetts uses a semi-closed primary system. Voters registered with a political party may vote only in that party's primary. Unenrolled voters, who are not registered with a political party, may choose to vote in either the Democratic or Republican primary without permanently enrolling in that party.

Voters registered with one political party cannot vote in another party's primary unless they change their party registration by the applicable deadline. Unenrolled voters who select a party's primary ballot remain unenrolled after voting.

Massachusetts does not hold primary runoff elections. Candidates only need to receive a plurality of the vote to win their party's nomination, meaning the candidate with the most votes becomes the party's nominee even if they do not receive an outright majority.