In the United States, the answer to this question depends on the state in which you are living. Some states permit same-sex couples to get married while other states do not. As of today (January 14, 2014), there are 17 states in which same-sex couples can legally get married. Such marriages are also legal in the District of Columbia. In all of the other states, there is no recognition of same-sex marriages. Federal law makes it so that states that do not allow gay marriage do not have to recognize gay marriages performed in states where such marriages are legal.
Same-sex marriages were made legal by court decisions in 6 of the 17 states in which such marriages are permitted. These states are California, Connecticut, Iowa, Massachusetts, New Jersey, and New Mexico. A court in Utah has ruled that gay marriage must be made legal in that state, but the Supreme Court of the United States has issued a stay of that ruling while the issue is being appealed.
In 8 states, legislatures passed laws making same-sex marriages legal. These states are Delaware, Hawaii, Illinois, Minnesota, New Hampshire, New York, Rhode Island, and Vermont. In the other three states that allow gay marriages, popular votes were taken that made such marriages legal. These states were Maine, Maryland, and Washington.
So, gay marriages are legal in about one-third of the states of the United States.