Bill Cosby and Roman Polanski have been expelled from the US Academy of Motion Picture Arts and Sciences.
The academy - which runs the Oscars - said this was done in accordance with its standards of conduct.
TV star Cosby was convicted of sexual assault last month. Oscar-winning director Polanski admitted statutory rape of a 13-year-old girl in 1977.
Neither Cosby nor Polanski have publicly reacted to the academy's decision.
The prestigious organisation made the announcement on Thursday - two days after its board members voted on the issue.
In a statement, it said its board "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," it added.
Only four people are known to have been expelled in its 91-year history.
The first was actor Carmine Caridi, who had his membership revoked in 2004 after he allegedly sent confidential film preview videos to a friend which ended up online.