The rally started at 9 a.m. in Cadman Plaza in Downtown Brooklyn. Following the speeches, the huge crowd began their march across the Brooklyn Bridge.
The Success Academy, the city's leading charter network, cancelled classes so students could attend.
Success Academy CEO Eva Moskowitz wrote in an email, "Unfortunately, anti-charter forces are powerful and we have had to fight for everything we have achieved over the past 20 years. There are currently serious threats to the educational excellence your child deserves."
Moskowitz did not specifically name Mamdani, an opponent of charter school expansion.
"New York debates every issue under the sun, but somehow the future of our young people-their education, their excellence-fails to get prioritized and keeps getting pushed aside," said Regina Seaborne, a parent at Ember Charter School. "We refuse to let our children's right to thrive be ignored."
"This rally is about equity, justice and opportunity," said Dream Charter School parent Samantha Robin. "Parents deserve the freedom to choose schools that honor their children's genius, their culture, and their potential."
Some 238 schools participated in the rally and march.
Meantime, Curtis Sliwa was expected to attend to show his support for charter schools, despite organizers discouraging mayoral candidates from showing up and speaking, saying the rally was meant to be non-political.
Jon Reinish, a spokesman for the Coalition of Charter Schools organed the march and rally. He said that no political candidates were invited to the event.
Andrew Cuomo approved laws supportive of charter schools when he was governor, and has an education plan that would shut down underperforming public schools and potentially replace them with charters.
Asked about charter schools on Tuesday, Cuomo said, "There is tremendous support" for them from "Tens of thousands of parents...and the logic is inarguable."
Opponents, including the teachers' union, say they siphon taxpayer dollars and students from traditional public schools.
"Public schools welcome and embrace all children and are determined to help all students thrive. Zohran Mamdani understands this. The leadership of the Success Academy charter chain never has. They continue to tell students and families who don't fit their mold to get out," Michael Mulgrew, president of the United Federation of Teachers.
More than 150,000 students currently attend 286 charter schools, nearly 15% of the city's publicly funded schools, according to the NYC Charter School Center.
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