Polygamy is not legal in Massachusetts. State law makes it a felony to marry a second person while a prior spouse is still living, and any such marriage is void from the moment it happens. A conviction can bring up to five years in state prison. A few Massachusetts cities do allow more than two people to register as domestic partners for local purposes, but that is not marriage and does not change the state’s bigamy rule.
What the Criminal Statute Covers
Massachusetts General Laws Chapter 272, Section 15 makes it a crime to marry someone while you have a living spouse. The same statute reaches further: it also criminalizes continuing to live within Massachusetts with a second spouse, even if the second ceremony happened in another state or country. You do not have to get married in Massachusetts to be prosecuted here. Moving in and living as a married couple while one of you is already married to someone else is enough.
Penalties are serious. A conviction can carry up to five years in state prison, or up to two and a half years in a jail or house of correction. The court can also impose a fine of up to $500, either on its own or alongside incarceration.1General Court of Massachusetts. Massachusetts Code Chapter 272 Section 15 – Polygamy
When a Second Marriage Is Not a Crime
The statute itself names two situations where remarrying does not trigger prosecution. A legal divorce ends the prior marriage, so remarriage afterward is simply remarriage. And the statute excuses a person whose spouse has been continuously absent for seven consecutive years when the remaining spouse had no reason to believe they were still alive at any point during that period.1General Court of Massachusetts. Massachusetts Code Chapter 272 Section 15 – Polygamy
The seven-year defense is narrower than it sounds. Any credible sign of life during the seven years, whether a letter, a message through a mutual acquaintance, or secondhand news, undermines it. The provision was written for genuinely vanished spouses, not for people who want a workaround.
The Second Marriage Is Legally Void
Criminal exposure is only half the picture. Massachusetts also treats a bigamous marriage as void from the start under Chapter 207, Section 4. A void marriage is not an annulled or divorced marriage. In the eyes of the state, it never existed at all.2General Court of Massachusetts. Massachusetts Code Chapter 207 Section 4 – Polygamy Prohibited; Exception
That has real financial consequences for the second spouse. Because there is no marriage, there is no spousal inheritance, no alimony, and no access to the property-division rules a divorcing couple would use. If the relationship ends, the second spouse is treated as an unmarried person who happened to have gone through a ceremony. Assets and debts are sorted out, if at all, under ordinary contract and property law.
The Good-Faith Lifeline
Chapter 207, Section 6 provides a limited rescue for someone who entered the second marriage without knowing it was invalid, whether because they believed the former spouse had died, believed a prior divorce had been finalized, or did not know about the earlier marriage at all. If the impediment is later removed, because the earlier spouse dies or gets divorced, and the couple keeps living together, the law treats them as legally married from the moment the impediment was removed. Children born during the invalid period are considered legitimate.3General Court of Massachusetts. Massachusetts Code Chapter 207 Section 6 – Marriage During Existence of Former Marriage; Validity
The protection is retroactive validation only. While the earlier marriage is still in force, the second marriage remains void and carries no legal weight, no matter how innocent the second spouse was.
Polyamory Is Not Polygamy
Many people asking this question are in polyamorous relationships and want to know where the legal line sits. Having more than one romantic partner is not illegal in Massachusetts. What the statute targets is marriage: either going through a second marriage ceremony while a prior marriage is still in force, or living with a “second husband or wife” in Massachusetts.1General Court of Massachusetts. Massachusetts Code Chapter 272 Section 15 – Polygamy
That cohabitation language is aimed at people presenting themselves as married to two people at once, not at modern polyamorous households where no one is claiming a second marriage. Still, the line between living together as spouses and living together as partners is not spelled out in the statute, and it has not been tested in court against today’s non-traditional households. People in these arrangements should know they are operating in an area the statute’s drafters did not have in mind.
Cities That Recognize Multi-Partner Domestic Partnerships
A small number of Massachusetts municipalities now allow more than two people to register as domestic partners. Somerville became the first city in the country to pass such an ordinance in 2020, defining a domestic partnership as “the entity formed by people” who meet its criteria, with no numerical cap. Cambridge adopted a multi-partner ordinance in 2021, and Arlington passed a bylaw recognizing partnerships of two or more people.4City of Somerville. City of Somerville Ordinance 2020-16 – Domestic Partnerships
Registration requires all partners to appear together before the city clerk or a notary and declare under penalty of perjury that they share a relationship of mutual support and commitment, live together, consider themselves a family, are not married, are not too closely related by blood, and are legally competent to contract.
What a registration actually gets you is limited to what a city government controls: access to municipal employee health benefits for all registered partners and hospital visitation rights at local facilities. These ordinances do not create a state-recognized marriage, and they do not override the state bigamy statute. You can register a three-person domestic partnership in Somerville and remain fully within state law, as long as no more than two of you are legally married to each other.
Federal Immigration Consequences
If anyone in the household is not a U.S. citizen, federal law adds a sharp risk. Under 8 U.S.C. ยง 1182(a)(10)(A), any immigrant coming to the United States to practice polygamy is inadmissible. No criminal conviction is required. The provision reaches intent, which means an immigration officer can deny entry or adjustment of status based on evidence of a polygamous relationship alone.5Office of the Law Revision Counsel. 8 USC 1182 – Inadmissible Aliens
Parentage When More Than Two Adults Are Raising a Child
Massachusetts limits its routine parentage paperwork to two parents. The Voluntary Acknowledgment of Parentage, which unmarried parents sign at the hospital, establishes one additional legal parent alongside the birth parent and has no space for a third.6Mass.gov. How to Establish Parentage
For a non-biological adult in a multi-partner household who wants recognized parental rights, the Massachusetts Parentage Act, effective January 1, 2025, created a statutory path through “de facto parent” status under G.L. c. 209C, Section 25. The requirements are substantial. You must have lived with the child for at least two years (and no less than three years or 40 percent of the child’s life, whichever is shorter), provided consistent caregiving without expectation of payment, taken on full parental responsibilities, held the child out as your own, and formed a bonded parental relationship. Every existing legal parent must have consented to that relationship, and the court must find that recognizing you as a parent is in the child’s best interest.7Mass.gov. Massachusetts General Laws c209C Section 25
De facto parent status is not automatic. It requires a court proceeding and proof by clear and convincing evidence. For adults in stable multi-partner households already raising a child together, it is the main legal route to parentage beyond the two-parent default, and the record you build over time, meaning how long you have cared for the child and in what capacity, is what the court will weigh.