The Supreme Court ruled on Thursday that states cannot ban same-sex couples from marrying under federal law.
The court overturned the lower court decision, saying it was unconstitutional.
In June, California became the first state to outlaw same-gender marriage.
That decision was later blocked by the U.S. Supreme Court.
The justices said states can ban same sex marriage if they want to.
The justices said it was not a “fundamental right” to marry, but rather a right of states to determine the rules of marriage and its definition, which must be upheld by the highest court in the land.