TikTok reached a settlement in a high-profile lawsuit accusing the platform of deliberately addicting and harming children, just days before the trial was set to begin. The case also involves Meta’s Instagram, Google’s YouTube, and Snap, and could shape the outcome of hundreds of similar lawsuits targeting social media companies over youth mental health.

Attorneys for the plaintiffs confirmed the settlement on Tuesday, though details remain undisclosed. TikTok did not respond to requests for comment. Snap had already settled last week for an undisclosed amount. Meta and YouTube remain defendants, and the trial will proceed against them in Los Angeles County Superior Court.

At the center of the case is a 19-year-old identified as KGM, whose claims serve as one of three bellwether trials. These test cases will help determine how juries respond to allegations that social media platforms intentionally designed addictive features to target children. Joseph VanZandt, co-lead counsel for the plaintiffs, said TikTok continues to face other personal injury lawsuits despite the settlement.

Jury selection began this week, with 75 potential jurors questioned daily. The trial marks the first time social media companies will defend themselves before a jury in cases alleging harm to children. The proceedings are expected to last six to eight weeks, with Meta CEO Mark Zuckerberg and other executives scheduled to testify.

Plaintiffs argue that companies borrowed techniques from slot machines and the tobacco industry to maximize youth engagement and advertising revenue. They claim these design choices worsened depression and suicidal thoughts among young users. Advocates compare the lawsuits to the Big Tobacco trials that led to a landmark 1998 settlement requiring cigarette companies to pay billions in healthcare costs and restrict marketing to minors.

Sacha Haworth, executive director of the Tech Oversight Project, said families continue to come forward with similar claims. “This is only the first case. Hundreds of parents and school districts are speaking out and bringing Big Tech to court for its deliberately harmful products,” she said.

Meta, Google, and other companies strongly deny the allegations. Meta said in a blog post that blaming teen mental health struggles solely on social media oversimplifies a complex issue. A spokesperson added that Meta remains confident the evidence will show its commitment to supporting young people. Google spokesperson José Castañeda said the claims against YouTube are “simply not true” and emphasized the company’s focus on safer experiences for young users.

The lawsuits extend far beyond this trial. More than 40 state attorneys general have sued Meta, accusing the company of harming children through addictive features on Instagram and Facebook. TikTok faces similar lawsuits in over a dozen states. In June, a federal bellwether trial in Oakland will represent school districts suing social media platforms over youth harms.

Meanwhile, New Mexico will begin jury selection next week in a separate case alleging Meta failed to protect children from sexual exploitation. Prosecutors argue Meta’s algorithms amplified harmful content, citing internal documents estimating that 100,000 children face harassment daily on its platforms. Meta responded by highlighting its use of advanced technology, child safety experts, and collaboration with law enforcement to combat exploitation.

This settlement marks only the beginning of a wave of trials that could redefine accountability for social media companies and their role in shaping the mental health of young users.