Ryan O'Neal -- Screw You UT ... Andy Warhol's Farrah Fawcett Painting is MINE!

Ryan O'Neal shockingly just won a huge lawsuit over who owns an extremely expensive Andy Warhol painting of Farrah Fawcett.

The University of Texas -- Farrah's alma mater -- sued Ryan, claiming the actress had gifted the painting to the school in her will. Ryan, who is in possession of the Warhol, claimed the artist himself gave him the painting to show his appreciation for setting up the portrait sitting with his ex.

The value of the picture could be as high as $12 mil on the open market.

It seemed the will was going to sink Ryan, but the jury sided with Ryan.

Good thing. Last week he told TMZ ... if he didn't win he'd die.