How a Bill Becomes Law in Massachusetts

Updated Oct. 17, 2026. Deadlines and rules checked against official sources on that date.

The Massachusetts Legislature, formally called the General Court, has two chambers: a 40-member Senate and a 160-member House of Representatives. Each two-year legislative session starts in January of odd-numbered years, and thousands of bills are filed at the start of each one. Only a small share become law. This guide follows a bill from filing to the governor’s desk, based on the state’s own description of the process and guides from the Massachusetts Bar Association and Massachusetts Legal Services.

1. Filing

A legislator files a bill with the clerk of the House or Senate. Massachusetts also has a “right of free petition,” which lets residents ask a legislator to file a bill on their behalf. Each bill gets a number, H. for House bills and S. for Senate bills, and can be followed on malegislature.gov.

2. Joint committee and public hearing

Unlike most states, Massachusetts sends nearly every bill to a joint committee made up of members of both chambers, organized by subject, such as housing or transportation. The committee must hold a public hearing on each bill, where anyone may testify. It then reports the bill favorably (“ought to pass”), with amendments, as a redraft that may combine several bills, unfavorably (“ought not to pass”), or to a study order, which for most bills ends their progress. Joint rules set a deadline for committees to report, though extensions are common.

3. Three readings

A favorable report counts as the first reading. Bills that spend money usually go next to the Ways and Means committee of that chamber; others may go to a steering and policy committee. At the second reading, the bill is debated on the floor and amendments are offered. It then goes to the Committee on Bills in the Third Reading, which reviews it for legal form, constitutionality and conflicts with existing law. After the third reading, members may debate and amend again before voting on whether to pass the bill “to be engrossed.”

4. The other chamber

An engrossed bill moves to the other chamber, where it goes through the same readings. If the second chamber changes the bill, the first chamber can accept the changes. If it does not, a conference committee of members from both chambers negotiates a single version, which both chambers must then accept without further amendment. Many of the biggest bills each session, including the state budget, are settled in conference committees.

5. Enactment

Once both chambers have passed the same text, the bill is printed on parchment by the Legislative Engrossing Division and returns for final enactment votes, first in the House and then in the Senate. Enactment is usually a formality, though a bill can still be debated or rejected at this stage.

6. The governor

The governor then has 10 days to act. The governor can sign the bill, veto it with a written explanation, return it with recommended amendments, or let it become law without a signature after 10 days. If the Legislature has ended its formal session before the 10 days are up and the governor does not sign, the bill dies; this is called a pocket veto. Overriding a veto takes a two-thirds vote of each chamber. On spending bills, the governor can veto or reduce individual line items.

7. When laws take effect

Under the state constitution, most new laws take effect 90 days after they are signed, which leaves time for citizens to seek a referendum. A law can take effect immediately if it carries an emergency preamble. Question 9 on this year’s ballot is an example of the referendum process: it asks voters whether to keep a firearms law passed by the Legislature.

How to follow a bill

Search by bill number, keyword or sponsor on malegislature.gov to see a bill’s text, committee, hearing dates and recorded votes. The site’s “Find My Legislator” tool shows who represents your address. For bills in Congress instead of the State House, see Congress.gov and our Congress Tracker.