The case brought by the NRA centers on whether the Constitution guarantees the right to carry guns outside the home.
The city's brief says this could threaten the ability to regulate concealed handguns in the city.
"Great policing, great community involvement and strong gun laws, that's what allowed us to become the safest big city in America," Mayor Bill de Blasio said. "We're going to do everything we can to ensure the NRA does not get its way and guns are not more present on the streets of New York City."
The Supreme Court will hear oral arguments on Nov. 3.
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