Romney said he would file a legal action this week asking a justice of the Supreme Judicial Court to direct the secretary of state to place the question on the ballot if lawmakers don't vote directly on the question Jan. 2, the final day of the session.
Romney, an opponent of gay marriage who decided not to seek re-election as he considers running for president, made his announcement to the cheers of hundreds of gay marriage opponents at a rally on the Statehouse steps.
People in favor of gay marriage staged a protest across the street.
The Massachusetts Supreme Judicial Court ruled in November 2003 that such marriages were legal. Since then, more than 8,000 same-sex couples have tied the knot in the state.
More than 170,000 people had signed a petition in support of the ballot question, which would define marriage as between only a man and a woman.
Romney has criticized lawmakers since they refused earlier this month to take up the question during a joint session, voting instead to recess until Jan. 2 and all but killing the measure.
"A decision not to vote is a decision to usurp the Constitution, to abandon democracy and substitute a form of what this nation's founders called tyranny, that is, the imposition of the will of those in power, on the people," Romney said earlier. "The issue now before us is not whether same-sex couples should marry. The issue before us today is whether 109 legislators will follow the Constitution."
Because the Legislature is in recess and did not adjourn, Romney has no legal authority to call lawmakers back into session.
Supporters of gay marriage defended lawmakers' procedural move.
"One of the tenets of the Constitution is that you do not put the rights of a minority up for a popularity contest," said Mark Solomon, campaign director of Mass Equality, a pro-gay marriage group. "It is one of the very principles this country was founded upon."
Messages seeking comment from legislative leaders were not immediately returned Sunday.
The Legislature grappled with various efforts to ban same-sex marriages even before the high court ruling in 2003. Lawmakers refused to vote on a citizens' initiative in 2002, and two years later voted down their own proposed amendment that would have banned gay marriage and legalized civil unions.
In the November elections, amendments to ban gay marriage passed in Colorado, Idaho, South Carolina, South Dakota, Tennessee, Virginia and Wisconsin. Only Arizona defeated such an amendment.
Vermont and Connecticut have legalized civil unions that give same-sex couples benefits similar to marriage. New Jersey's highest court has ordered the Legislature to allow either marriage or civil unions for same-sex couples.