Sen. President Richard Codey has scheduled the vote for Thursday. Codey said Tuesday that the people of New Jersey "deserve the right to a formal debate on the Senate floor."
Five states now recognize gay marriage. Gay rights advocates have been pushing for New Jersey to join them quickly.
Gov. Jon Corzine supports the measure. But Chris Christie, who will replace him in two weeks, says he would veto it.
A Senate vote was canceled last month because it appeared the measure was going to fail. If it passes the Senate, it would still need the approval of the state Assembly to be sent to the governor's desk.