Mass. Gen. Laws ch. 53 § 18A
As used in this section "governing body" shall mean, in a city, the city council acting with the approval of the mayor subject to the provisions of the charter of said city, in a town having a town council, the town council, and in every other town the board of selectmen.
A nonbinding public opinion advisory question may be placed on the ballot for a regular municipal election in any city or town no later than the thirty-fifth day preceding such election: by vote of the city council of such city, with approval of its mayor where so required by the city charter; by vote of the board of selectmen of a town or by vote of the town council of a town having a town council or by vote of the annual town meeting; or in conformity with the following provision of this section:
A proposal to place a nonbinding public opinion advisory question on the ballot for a regular municipal election in any city or town may be presented to the governing body thereof on a petition signed by at least ten registered voters of the city or town. If such governing body shall not approve said petition at least ninety days before said election, then the question may be so placed on said ballot when a petition signed by at least ten per cent of the registered voters of the city or town, but in no case less than twenty such voters, requesting such action is filed with the registrars, who shall have seven days after receipt of such a petition to certify the signatures. Upon certification of the signatures, the city or town clerk shall cause the question to be placed on the ballot at the next regular municipal election held more than thirty-five days after such certification.
The procedures established by this section shall be available to any city or town; provided, however, that if an alternative procedure is prescribed by a home rule charter, optional plan of government, or special act applying to such city or town, relative to the placing of public opinion questions upon the local ballot, then such alternative procedure shall apply.
Mass. Gen. Laws ch. 53, § 18A