Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 140, § 139

(a) The fee for a license shall, except as otherwise provided, be determined by a city or town; provided, however, that no fee shall be increased without a majority vote of the city or town council or the voters present at a town meeting.

(b) The license fee for a spayed or neutered dog shall be less than the license fee for an intact dog. Upon application for a license, a city or town clerk shall require a certificate from the veterinarian who spayed or neutered the dog as proof that the dog is spayed or neutered; provided, however, that if the city or town clerk is satisfied that the certificate of the veterinarian who spayed or neutered the dog cannot be obtained, the clerk may instead accept a receipt of a bill from the veterinarian who performed such procedure or a statement signed under the penalties of perjury by a veterinarian registered and practicing in the commonwealth describing the dog and stating that the veterinarian has examined the dog, which appears to have been spayed or neutered and incapable of propagation.

(c) No fee shall be charged for a license issued under this section for a service animal as defined by the Americans with Disabilities Act or regulations promulgated thereunder. No fee shall be charged for a license for a dog owned by a person aged 70 years or over in a city or town that accepts this provision. No license fee or portion thereof shall be refunded because of the subsequent death, loss, spaying or removal from the commonwealth or other disposal of the dog, nor shall a license fee or portion thereof paid by mistake be paid or recovered after it has been paid over to a city or town under section 147.