Same-sex marriage in Spain was legalised in 2005. In 2004, the new Socialist government, led by President José Luis Rodríguez Zapatero, began a campaign for its legalization, which would include adoption by same-sex couples. After much debate, a law permitting same-sex marriage was passed by the Cortes Generales on 30 June 2005 and published on 2 July 2005. Same-sex marriage officially became legal in Spain on Sunday, 3 July 2005. The ratification of this law has not been devoid of conflict, despite support from 66% of Spaniards. Catholic authorities in particular were adamantly opposed to it, fearing the weakening of the meaning of marriage. Demonstrations for and against the law drew thousands of people from all parts of Spain.
Approximately 4,500 same-sex couples have married in Spain during the first year of the law. Shortly after the law was passed, questions arose about the legal status of marriage to non-Spaniards whose country did not permit same-sex marriage. A ruling from the Spanish Justice ministry stated that the country's same-sex marriage law allows a Spanish citizen to marry a non-Spaniard regardless of whether that person's homeland recognizes the partnership. At least one partner must be a Spanish citizen to marry.