In a packed Los Angeles courtroom on Wednesday, Meta CEO Mark Zuckerberg delivered defiant testimony in a high-stakes trial accusing social media platforms of contributing to teen mental health crises. The 41-year-old billionaire, testifying for the first time before a jury, pushed back against claims that Instagram and Facebook are engineered to addict users, particularly young ones, through algorithms and features that prioritize engagement over well-being. The case, centered on plaintiff K.G.M., a 20-year-old Californian who alleges the platforms exacerbated her depression and suicidal tendencies after she began using them at age 10, could reshape liability for tech giants under Section 230 of the Communications Decency Act.
Zuckerberg, dressed in a dark suit and occasionally wearing a gold chain, faced intense questioning from plaintiff's attorney Mark Lanier in Los Angeles Superior Court before Judge Carolyn Kuhl. The trial, which began on February 9, 2026, has already seen TikTok and Snap settle confidentially with the plaintiffs, leaving Meta and Google as the remaining defendants in this California action and a parallel case in New Mexico. Unlike his rivals, Zuckerberg showed no inclination toward settlement, asserting instead that Meta's focus is on long-term user satisfaction rather than short-term addiction.
“I’m focused on building a community that is sustainable,” Zuckerberg told Lanier when pressed on the platforms' algorithms and auto-feeds, which plaintiffs argue create obsessive usage patterns. He added, “If you do something that’s not good for people, maybe they’ll spend more time short term [on Instagram], but if they’re not happy with it, they’re not going to use it over time.” The CEO denied any intent to maximize monthly user time, despite a 2015 email he authored urging staff to significantly increase “time spent” on Facebook and Instagram.
Lanier challenged Zuckerberg directly on his role as the company's decision-maker. “Sir, you are the decision maker for your whole company,” the attorney exclaimed in the courtroom, which was filled with parents and, briefly, K.G.M. herself. The exchange highlighted tensions over internal documents from discovery, including reports from Meta's own researchers warning of harms to young users and the prevalence of children under 13 on the platforms.
Meta's defense, outlined in a pre-trial statement, shifts blame away from Instagram. “The question for the jury in Los Angeles is whether Instagram was a substantial factor in the plaintiff’s mental health struggles,” the company said. “The evidence will show she faced many significant, difficult challenges well before she ever used social media.” Zuckerberg echoed this during testimony, suggesting that age verification is limited because “some people simply ‘lie’ about their age” to access the platforms, and Meta only implemented robust systems in recent years.
The testimony grew heated when Lanier referenced Zuckerberg's past statements on child safety, including comments made on Joe Rogan’s podcast. “You’re mischaracterizing this,” Zuckerberg snapped, accusing the lawyer of taking his words out of context. He also debated Lanier on the distinction between “goals” and “milestones” in user growth metrics, downplaying reports of underage users as unavoidable in a system reliant on self-reported data.
Judge Kuhl intervened early in the proceedings to assert courtroom authority, particularly over Meta's wearable technology. She warned Zuckerberg's aides and others donning Ray-Ban Meta smart glasses that she would hold them in contempt if any recording occurred via the devices. “Take them off ASAP,” the judge demanded, an order that underscored the scrutiny on Meta's innovations amid allegations of exploitative design.
As an adverse witness, Zuckerberg faced broader leeway in questioning, a status that allowed plaintiffs to probe deeply into Meta's practices. The company had previously sought dismissal under Section 230 and First Amendment protections, arguments Judge Kuhl rejected in November 2025. She ruled that the defendants “were capable of causing the type of mental harms allegedly suffered,” paving the way for the trial to proceed.
K.G.M.'s allegations paint a stark picture of social media's impact. Starting on the platforms at just 10 years old, she claims the dopamine-driven feeds and personalized algorithms led to her mental health decline, including deep depression and suicidal ideation. To dramatize this, Lanier concluded his questioning by unfurling a 50-foot scroll displaying dozens of selfies K.G.M. had posted using Instagram's beauty filters. Zuckerberg remained silent as the images were presented to the jury.
The California trial runs parallel to a case in New Mexico led by Attorney General Raúl Torrez, where similar claims against Meta are being litigated. Following Wednesday's testimony, Torrez criticized Zuckerberg's performance. “In a California courtroom today, Mark Zuckerberg refused to admit what witnesses in our trial have repeatedly shown: Meta prioritizes profits over children’s safety,” Torrez told Deadline. He added, “In the New Mexico Department of Justice’s trial against Meta, it has become clear that Mark Zuckerberg and Meta have misled the public about the dangers of its products that its own researchers have known for years. Parents need to know about Meta’s pattern of deceit and the real dangers children face on these platforms.”
YouTube CEO Neal Mohan was originally listed as a witness but has since been marked absent, with no explanation provided. This development leaves unanswered questions about Google's role, as the tech giant remains a co-defendant. The trials represent a pivotal moment for the industry, potentially eroding long-standing immunities if plaintiffs prevail.
Broader context underscores the stakes. Social media companies have long enjoyed protections under Section 230, which shields them from liability for user-generated content. A victory for K.G.M. could invite a wave of similar lawsuits, challenging the addictive nature of features like infinite scrolls and notifications. Appeals are likely if Meta loses, prolonging the legal battle and its implications for tech regulation.
Experts and observers note the rarity of a CEO like Zuckerberg facing jury cross-examination. His past appearances, including stiff Congressional hearings, have often drawn criticism for scripted responses. Wednesday's testimony, however, revealed a more combative side, as he defended Meta's mission amid growing public and regulatory pressure on youth safety.
As the trial continues in downtown Los Angeles, the focus remains on balancing innovation with responsibility. With standing-room-only crowds and national attention, the outcome could influence not just Meta but the entire social media landscape, prompting calls for stronger safeguards against digital harms.
For now, Zuckerberg's defiance sets the tone, but the jury's deliberation will ultimately decide if platforms like Instagram bear substantial responsibility for the mental health struggles of users like K.G.M.