Mass. Gen. Laws ch. 30 § 24
All offices under the jurisdiction of any department of the state government shall be open to the public for the transaction of business daily on days other than Saturdays, Sundays and legal holidays for such hours, beginning not later than nine o'clock in the forenoon and ending not earlier than five o'clock in the afternoon, as may be set by the department head subject to the approval of the commissioner of administration, except that, if the convenience of the public so requires, any department head, subject to like approval, may keep any office under his jurisdiction open on any Saturday, not a legal holiday, from nine o'clock in the forenoon to twelve o'clock noon, and give any employee required to work on Saturday equivalent time off without loss of compensation. When the day or the last day for the performance of any act, including the making of any payment or tender of payment, authorized or required to be performed at such an office falls on a Saturday, Sunday or legal holiday, the act may be performed on the next succeeding business day.
Mass. Gen. Laws ch. 30, § 24