A statement from the organisation behind the Oscars said: “The Academy of Motion Picture Arts and Sciences’ board of governors met on Tuesday night (1 May) and has voted to expel actor Bill Cosby and director Roman Polanski from its membership in accordance with the organisation’s standards of conduct.
“The board continues to encourage ethical standards that require members to uphold the academy’s values of respect for human dignity.”
Cosby was last week convicted of sexual assault.
Polanski remains a fugitive after fleeing the US in 1978, having pled guilty to unlawful sex with a teenager.
The Academy expelled film producer Harvey Weinstein in October following numerous allegations of sexual misconduct.
Polanski, who won a best director Oscar for The Pianist, has been in self-imposed exile since he fled the US 40 years ago, fearing a judge would extend his sentence after he served 42 days in jail.
He pleaded guilty to having unlawful sex with Samantha Geimer in 1977 after allegedly plying her with champagne and a sedative at the Hollywood Hills home of Jack Nicholson, who was not there at the time.
Polanski, 84, is currently living in Paris, France.
Cosby, 80, is awaiting sentencing following his conviction for drugging and molesting a woman at his mansion in Philadelphia in January 2004.