Andrew Tate is going on the legal offensive against his ex-girlfriend Bri Stern … he’s now countersuing her, claiming she defamed him with what he says are fabricated allegations of sexual assault and abuse.

In new legal docs, obtained by TMZ, Andrew claims Bri orchestrated a deliberate smear campaign against him based on false claims that he choked her during sex despite telling him to stop.

Andrew claims Bri spread the false allegations in the media and online … and he says she was out for profit, fame, and the destruction of his reputation.

We broke the stories … Bri filed a police report in Beverly Hills back in March, claiming he attacked her during sex. She later hired Texas attorney Tony Buzbee and sued Tate for sexual assault.

Andrew vehemently denied her claims from the jump … and he says her allegations were contradicted by medical evidence and expert analysis showing the alleged injuries aligned more with cosmetic procedures than assault.

Tate also claims Bri was out to exploit his name, likeness and persona to promote her cryptocurrency and adult content ventures … and he even says she tried to extort another man in 2022 with similar allegations.

As we first reported … prosecutors declined to charge Andrew with a crime … and in his suit, he says Bri kept spreading her false abuse claims even after prosecutors declined the case due to insufficient evidence.