The court's 5-4 ruling struck down the District of Columbia's 32-year-old ban on handguns as incompatible with gun rights under the Second Amendment, but probably leaves most firearms laws and restrictions intact.
The court had not definitively interpreted the Second Amendment since its ratification in 1791 and had not heard a Second Amendment rights case in more than 70 years.
The Second Amendment reads: "A well regulated militia, being necessary to the security of a free state, the right of the people to keep and bear arms, shall not be infringed."
The basic issue for the justices was whether the amendment protects an individual's right to own guns or whether that right is somehow tied to service in a state militia.
Justice Antonin Scalia, writing in the majority opinion, said the Constitution does not permit "the absolute prohibition of handguns held and used for self-defense in the home."
Joining Scalia were Chief Justice John Roberts and Justices Samuel Alito, Anthony Kennedy and Clarence Thomas.
In dissent, Justice John Paul Stevens wrote that the majority "would have us believe that over 200 years ago, the Framers made a choice to limit the tools available to elected officials wishing to regulate civilian uses of weapons."
The other dissenters were Justices Stephen Breyer, Ruth Bader Ginsburg and David Souter.
Justice Breyer wrote a separate dissent in which he said, "In my view, there simply is no untouchable constitutional right guaranteed by the Second Amendment to keep loaded handguns in the house in crime-ridden urban areas."
Scalia said nothing in Thursday's ruling should "cast doubt on long-standing prohibitions on the possession of firearms by felons or the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings."
The law adopted by Washington's city council in 1976 prohibits residents from owning handguns unless they had one before the law took effect. Shotguns and rifles may be kept in homes if they are registered, kept unloaded and either disassembled or equipped with trigger locks.
Dick Anthony Heller, 66, an armed security guard and District resident, sued the city in 2003 after it rejected his application to keep a handgun at his home for protection.
The U.S. Court of Appeals for the District of Columbia ruled in Heller's favor and struck down Washington's handgun ban, saying the Constitution guarantees the right to own guns and that a total prohibition on handguns is not compatible with that right.
