Over 7.6 million people held demonstrations on streets and squares -- almost equal to the 2003 anti-Iraq war protest, making it one of the biggest global demonstration in the history of protests, the 350 Movement said.
"More than 6,100 events were held in 185 countries, with the support of 73 Trade Unions, 820 civil society organizations, 3,000 companies and 8,500 websites," the climate action group said in a statement, Anadolu Agency reported.
Celebrities such as Leonardo DiCaprio, Keith Richards, Mick Jagger and Chris Hemsworth supported the strike on social media.
Italy, Germany, Canada, the US, and Spain were the five countries where most people attended the global climate strike, the statement added.
"While young climate activists were giving powerful speeches to the authorities, only a few meters away major multinational oil company CEOs were meeting with government representatives and diplomats in another lobbying effort to shape and influence climate policy," the movement said, referring to meetings on the sidelines of the UN General Assembly session in New York.
It stressed the importance of meeting the Paris Agreement goals and cutting global emissions of greenhouse gases while criticizing big fossil fuel companies.
"While the planet heats up and entire communities lose their lives and livelihoods, the big fossil fuel companies keep profiting from coal, oil and gas," the statement concluded.