With its ruling in Goodridge v. Department of Public Health, the Massachusetts Supreme Judicial Court made the state the first in the U.S. to legalize same-sex marriage.

Goodridge v. Dept. of Public Health, 798 N.E.2d 941, is a landmark Massachusetts Supreme Judicial Court case in which the Court held that the Massachusetts Constitution requires the state to legally recognize same-sex marriage. The November 18, 2003, decision was the first by a U.S. state's highest court to find that same-sex couples had the right to marry. Despite numerous attempts to delay the ruling, and to reverse it, the first marriage licenses were issued to same-sex couples on May 17, 2004, and the ruling has been in full effect since that date.

The Massachusetts Supreme Judicial Court (SJC) is the highest court in the Commonwealth of Massachusetts. Although the claim is disputed by the Supreme Court of Pennsylvania, the SJC claims the distinction of being the oldest continuously functioning appellate court in the Americas, with a recognized history dating to the establishment of the Massachusetts Superior Court of Judicature in 1692 under the charter of the Province of Massachusetts Bay.

Same-sex marriage, also known as gay marriage, is the marriage of two people of the same legal sex. As of 2025, marriage between same-sex couples is legally performed and recognized in 38 countries, with a total population of 1.5 billion people. The most recent jurisdiction to legalize same-sex marriage is Thailand.