Mass. Gen. Laws ch. 71, § 41B

A school superintendent shall grant to a teacher who has been accepted to serve in the Peace Corps of the United States and who is currently in good standing in a public school of the commonwealth a leave of absence for the term of such service. Such leave shall be without pay and shall not be counted as creditable service for retirement purposes but such member shall be restored to his previous or a similar position, with the same status, pay, length of service credit and seniority, whenever applicable, as he held on the date of such leave of absence.