T.I. Sues Former Friend Sabrina Peterson for Defamation

T.I. is suing Sabrina Peterson for defamation over 3 years after she sued the rapper and made damning allegations about him ... including a claim he once held a gun to her head.

In new court documents obtained by TMZ ... T.I. claims he and his family ended their friendship with Sabrina, saying she wasn't a "positive" influence to be around.

The rapper alleges Sabrina felt spurned by this decision and, in turn, became obsessed with him and his family ... prompting SP to harass and threaten them by posting "false" and "baseless" accusations about them on social media.

T.I. says Sabrina's posts about himself and his family are defamatory and uploaded in the sole interest of harassing his loved ones.

The rapper says he isn't the first person to be victimized by Sabrina's online behavior ... claiming others have successfully sought legal protection from her alleged antics.

T.I. is seeking unspecified damages ... claiming he has suffered from her actions.

This is just the latest update in the legal saga between T.I. and Sabrina ... who sued T.I. and his wife, Tiny, for defamation back in 2021.

As TMZ previously reported, Sabrina alleged that the couple smeared her good name after she spoke out about the music mogul allegedly holding a gun to her head.

She also previously insinuated that T.I. and Tiny drugged and sexually abused women.

T.I. and Tiny denied the allegations at the time -- with their lawyer blasting it as "a sordid shakedown campaign."