Hawaii ended its defense of a law upholding biblical marriage on Monday, May 5.
The state had been fighting a lawsuit that challenged the definition of marriage as being between a man and a woman since 2011.
Attorney General David M. Louie explained why the state would no longer protest the litigation.
"The law, policy and public sentiment in Hawaii has clearly and dramatically changed in favor of marriage equality," Louie said in a statement.
Hawaii had been defending biblical marriage for years.
A law barring same-sex couples from receiving marriage licenses reached the Hawaii Supreme Court, and was upheld in 1999. The previous year, voters approved a constitutional amendment defining marriage as the union of a man and a woman.
In 2010, Former Governor Linda Lingle vetoed a bill that would have allowed same-sex civil unions, but Governor Neil Abercrombie allowed the unions in a 2011 decision. The first civil union ceremonies were conducted in January 2012.
In 2011, a gay couple filed a lawsuit against the state, stating that its ban of same-sex marriage was unconstitutional.
Although Governor Abercrombie was originally named a defendant in the suit, he voiced his support for the plaintiffs in court documents.
In November 2013, Abercrombie signed the Hawaii Marriage Equality Act, legalizing gay marriage in the state. The law took effect in December 2013.
Hawaii is the latest state to legalize same-sex marriage after the U.S. Supreme Court allowed married gay couples to receive federal benefits in June 2013.
In addition to Washington D.C., the states that allow gay marriage are: California, Connecticut, Delaware, Hawaii, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Hampshire, New Jersey, New Mexico, New York, Rhode Island, Vermont, and Washington.