A New York City Police Department spokesman said police responding to an emergency call made around 6.30 p.m. ET (2230 GMT) on Thursday found the man badly burned.
He was taken to Bellevue Hospital where he was pronounced dead, police said, adding an investigation was ongoing.
Police did not name the man and did not provide any potential motive for his action.
Voice of Tibet, a media outlet of exiled Tibetans, said Tibetan activist Lobga Rangzen "self-immolated outside the UN headquarters in New York after a live appeal for Tibetan independence and unity."
He was an Uber driver and went to the scene with a Tibetan flag, local news site amNewYork reported.
The website quoted fellow Uber driver Lobsang Paljor as saying he knew Rangzen from gatherings in the Tibetan community.
Paljor told the news website that Rangzen "was enraged by the restrictions the Chinese government had placed on his countrymen."
The United States and the European Union have expressed concern about China's new ethnic unity law, which went into effect this week and gives Beijing the legal basis to take action against people outside its borders.
The law, creates a "shared" national identity among the country's 55 ethnic minority groups, including Tibetans and Uyghurs, some of whom chafe under Chinese governance. Tibetans around the world have opposed the law.
Tibetans have also previously committed acts of self-immolation in protest against Beijing's policies in Tibet and nearby regions with large Tibetan populations.
China seized control of Tibet in 1950 in what it describes as a "peaceful liberation" from feudalistic serfdom.
-Reuters






