Gibson, star of "Lethal Weapon" and "Braveheart," has become a polarizing figure in Hollywood after making anti-Semitic remarks to a police officer during a drunken driving arrest several years ago. He has since apologized for his behavior.
Audio of Gibson allegedly uttering racial slurs during a heated argument with his ex-girlfriend, who has accused him of domestic violence, hit the Internet this summer.
Ryder -- who starred in "Lucas," "Beetlejuice," "Edward Scissorhands," "Reality Bites," "Little Women" and "The Age of Innocence" in the 1980s and 1990s -- has kept a low profile since a 2002 conviction for shoplifting.
Ryder is enjoying a career revival in "Black Swan" and said in an interview for the January issue of GQ magazine she heard Gibson use anti-Semitic and homophobic expressions well over a decade ago.
"I remember, like, 15 years ago, I was at one of those big Hollywood parties. And he was really drunk. I was with my friend, who's gay. He made a really horrible gay joke. And somehow it came up that I was Jewish. He said something about 'oven dodgers,' but I didn't get it. I'd never heard that before. It was just this weird, weird moment. I was like, 'He's anti-Semitic and he's homophobic.' No one believed me!"
ABCNews.com said Gibson's publicist did not immediately respond to its request for comment Friday.