The decision was made two hours before the Wednesday night event because a crowd of more than 1,500 had gathered outside the venue, the university said in a statement.
"Of paramount importance this evening was the campus's commitment to ensure the safety and security of those attending the event, the speaker, those who came to engage in lawful protest, as well as members of the public and the Berkeley campus community," it said.
UC Berkeley police said one person was arrested from the protests and that a campus lockdown was lifted late Wednesday night. Police said that all normal campus business and classes would be held Thursday.
A similar event at UC Davis was also canceled.
The 32-year-old Greek-born British journalist is a senior editor for the conservative news and opinion website. He's been called a spokesperson for the so-called "alt-right" movement for his extreme views on Islam, social justice, and political correctness.
He's a self-proclaimed "internet troll" who has been widely criticized for being racist and misogynistic.
Passions started flaring around 4 p.m. between both sides on the Cal campus ahead of Yiannopoulos' 8 p.m. speech. The event is sponsored by the Berkeley College Republicans. The university has stressed it did not invite Yiannopoulos and does not endorse his ideas but is committed to free speech and rejected calls to cancel the event.
The protests turned violent shortly before 5 p.m. as the event approached, with demonstrators lighting fires and fireworks on the Cal campus.
Yiannopoulos spoke Monday night at Cal Poly in San Luis Obispo, where he drew a diverse crowd of opponents and supporters. Cal State police monitored the crowd closely. The sold-out event was sponsored by the Cal Poly chapter of the College Republicans and not by the university itself.
The barricades were up for the crowds expected ahead of Yiannopoulos' speech before protesters tore them down.
"We're doing this because we feel like we want to exercise our free speech," said President of the Berkeley College Republicans Jose Diaz. "We want to bring someone here on campus to help speak on issues that sort of opens the dialogue."
Berkeley's student union vandalized during protest
But there are many others who believe Yiannopoulos' rhetoric is hateful, even dangerous, and has no place on a public university campus.
"Chancellor Dirks in his statement said the Constitution does not allow him to restrict free speech, and that's not true," said protest organizer Mukund Rathi. "Universities restrict free speech all the time for educational and security reasons."
Last month, Yiannopoulos' planned appearance at U.C. Davis was canceled at the last minute due to security concerns.
Yiannopoulos responded on Facebook after Wednesday's event was canceled, saying he had been "evacuated from the UC Berkeley campus after violent left-wing protestors tore down barricades, lit fires, threw rocks and Roman candles at the windows."
"We are confident that we have the plan and the pieces in place," said Dan Mogulof of U.C. Berkeley. "The law, ample court precedent, and the Supreme Cout could not be clearer that this event is fully and completely protected by the first amendment."
Twitter users reported that officers were firing rubber bullets at the protesters, and U.C. Berkeley police announced they were bringing in additional resources to handle the demonstration.
Pieter Sittler, a spokesman for the Berkeley College Republicans, said the club doesn't support everything Yiannopoulos says but "he gives a voice to repressed conservative thought on American college campuses." He uses "levity and humor" that should not be taken literally, Sittler said.
President Donald Trump reacted to the protests on Twitter, saying, "If U.C. Berkeley does not allow free speech and practices violence on innocent people with a different point of view - NO FEDERAL FUNDS?"
If U.C. Berkeley does not allow free speech and practices violence on innocent people with a different point of view - NO FEDERAL FUNDS?— Donald J. Trump (@realDonaldTrump) February 2, 2017
Yiannopoulos' talks have sparked protests, shouting matches and occasional violence at stops around the country. A man was shot and wounded at protests outside his Jan. 21 talk at the University of Washington.
Rowdy protests at UC Davis Jan. 13 prompted campus Republicans to cancel his appearance at the last minute. His final stop was supposed to be UCLA on Thursday but the invitation was rescinded, making Berkeley his grand finale.
The Associated Press contributed to this report.