But the gay marriage issue is a long way from being settled as forces on both sides gear up for more political battles.
Montgomery County senator, Robert Garagiola (D), sponsored the Civil Marriage Protection Act and he hailed the vote.
"It's a historic day for equal justice under the law," he says.
Some of the senators who voted against the legislation said they were following the wishes of their constituents.
"I have calls coming in 10 to one from my district saying this is not the way we want to go," says Prince George's County Sen. Anthony Muse (D).
Muse adds he also voted based on his religious beliefs.
Gay marriage opponents are hoping those callers who flooded their offices with messages and thousands more will support a referendum to repeal the measure once it becomes law.
"It's happened all over the country, ah, so I do believe there will be a petition drive on, on the ballot in 2012," says Sen. Ed DeGrange (D), who represents Anne Arundel County.
The House of Delegates' Judiciary Committee is expected to consider the measure on Friday.