The rejections came in one-line orders without comment.
A narrow Supreme Court majority ruled in 2008 that residents in the District of Columbia had a Second Amendment right to keep a handgun in the home for self-defense. The decision struck down the district's ban on the possession of handguns.
In 2010, a narrow high court majority ruled that the Second Amendment right applied to people in the states. That decision struck down Chicago's handgun ban.
Since those decisions, the high court generally has avoided gun control issues.
One of the rejected cases brought by the NRA challenged a Texas law that bans those under 21 from getting a gun permit. The other NRA challenge was to a federal law that puts restrictions on selling handguns to those under 21.
In both cases, the lower court had upheld the laws.
NBC News pointed out Texas defended its law in the Supreme Court -- putting state Attorney General Greg Abbott in the uncomfortable position of opposing the NRA while running for governor.