Craig Newmark, the Craigslist entrepreneur who arguably forced the newspaper industry to change its business model after his website put a dent in the lucrative classified ads business, is giving $20 million to the CUNY Graduate School of Journalism.

“In this time, when trustworthy news is under attack, somebody has to stand up,” Mr. Newmark said. “And the way you stand up these days is by putting your money where your mouth is, and that’s what I’ve done.”

As a result of the $20 million gift, which was announced on Monday, the school will change its name this summer to the Craig Newmark Graduate School of Journalism at the City University of New York. The donation, to be made through Craig Newmark Philanthropies, will fund an endowment for the school, which was founded in 2006.

“We’re very excited,” said Sarah Bartlett, the dean of the journalism school. She added that the money would help make up for the steady decline in state funding for the school, which receives limited donations from former students, who “are too young in their professions to be relied upon to make major donations,” Ms. Bartlett said.