It comes after parent company Meta Platforms, which also owns Facebook, allegedly ignored internal research about the physical and mental health dangers it posed to youth.
The investigation will look into the techniques used by the company to increase the amount of time young people spent on Instagram, and any harm caused by that extended time on the app.
It's being launched in the wake of recent reports that showed Instagram use is associated with a variety of mental health conditions, particularly for teen girls.
Those conditions include depression, eating disorders and suicide.
A statement from Attorney General Josh Shapiro said in part:
“We must do more to keep our children safe online — from both predatory people and predatory companies who put them at risk. Social media companies have a responsibility to keep their users safe and disclose risks associated with their platforms. Our investigation will help determine whether Facebook failed in its responsibility to protect children online and will help us determine how to stop these companies from continuing to put children at risk for their own profit.”
A bipartisan coalition of attorney generals is leading the investigation. It includes attorney generals from California, Florida, Kentucky, Massachusetts, Nebraska, New Jersey, Tennessee, and Vermont.