Associate Justice Clarence Thomas wrote the opinion for a 6-3 majority.
The case was among the most closely watched this term on a docket full of culture war issues such as abortion, religious freedom and climate change. The decision had the potential to shift the landscape on Second Amendment rights at a time when Americans remain divided over access to guns.
"New York’s proper-cause requirement violates the Fourteenth Amendment in that it prevents law-abiding citizens with ordinary self-defense needs from exercising their right to keep and bear arms," Thomas wrote in an opinion joined by five other conservative justices.