The $US16.68 billion ($A23.23 billion) agreement settles claims filed by 47 US states over social media harms to children.
California, Colorado, Kentucky and New Jersey were among 29 states that sued the tech giant in 2023 but the deal cuts short the trial, which was expected to include chief executive Mark Zuckerberg taking the stand before a jury in federal court in California.
The agreement is worth $US353 million in the state of Virginia alone and is one of the biggest in state consumer protection history, Attorney General Jay Jones said in a statement.
"For years, Meta intentionally deceived the public about the addictive and harmful design features that have wreaked havoc on youth mental health," Jones said.
The settlement "will put an end to these dangerous practices and deliver meaningful relief that will protect children from online harm".
Meta said in a blog post that it was "building on our longstanding efforts to empower parents and support teens".
"Ensuring teens have a safe and productive experience on our platforms is an absolute imperative for Meta," the company said.
"We want to get this right for parents and teens, and that's why we partnered with state attorneys general to set a new industry standard."
The company urged its rivals to adopt similar safety measures.
The settlement sum is a fraction of the company's 2025 revenue of $US201 billion.
The lawsuit accused Meta of contributing to the youth mental health crisis by deliberately designing features that addict children to its platforms and hiding them from the public.
It also argued that Meta violated US federal laws by routinely collecting data on children under 13 without their parents' consent.
The trial kicked off last week in Oakland, California, with US District Judge Yvonne Gonzalez Rogers overseeing the proceedings.
Adam Mosseri, the head of Instagram, began his testimony late on Tuesday and defended Meta's record and progress on child safety and privacy.
The cases in other states had been expected to go to trial later.
In addition, nine attorneys general filed lawsuits in their respective states.
Under the proposed settlement, Meta agreed to adopt a series of safety features, including a "hard cap" on daily time limits and pauses for children using Instagram and Facebook.
It will eliminate push notifications during weekday school hours and bring in "robust" age-assurance measures and "age-appropriate" content controls to prevent bullying and harmful material about eating disorders and self-harm.
There will be stronger and more user-friendly parental controls and limits on social comparison features such as "like" counts.
with AP
