After reconciliation between the two chamber versions, the Religious Freedom and Marriage Freedom Act will go to Gov. Pat Quinn, a Democrat, who has said he would sign it into law.
The Chicago Tribune said the bill got 61 votes in the House, one more than the bare minimum needed to send it back to the Senate for final approval.
In a statement, Marc Solomon, Freedom to Marry's national campaign director, said the vote by the Illinois House "means the Land of Lincoln will be our nation's 15th freedom to marry state. This is great news for the thousands of committed same-sex couples in Illinois who will now be able to make the ultimate vow before their friends and family, protected and supported by their marriage. It also represents tremendous momentum, with another victory in the heartland and our sixth state victory in 2013."
The organization campaigns to allow same-sex marriage nationwide.
When the roll call on the bill was completed, the crowd in the packed House galleries broke into cheers, and openly gay state Democratic Rep. Greg Harris of Chicago was swarmed by fellow House members, the Chicago Sun-Times reported.
One opponent, fellow Chicago Democrat Rep. Mary Flowers, cited the Bible and said same-sex couples will "not be truly married in God's eyes" despite the actions of the Legislature. the Chicago Tribune reported.