New York's highest court overturned Weinstein's 2020 rape conviction by 4 votes to 3.
The court found that the judge presiding over the landmark #MeToo case had improperly biased Weinstein.
The ruling, which found an abuse of judicial discretion, cited the judge's decision to allow women to testify about allegations that were not part of the case as one of the most prominent examples.
The case can be retried
"We conclude that the trial court erroneously admitted testimony of uncharged, alleged sexual acts against persons other than the complainants of the underlying offenses," the court's ruling said.
"The remedy for these egregious errors is a new trial," the court concluded.
The court's decision could mean that Weinstein's accusers will have to tell their stories on the witness stand again.
The #MeToo era began in 2017 with a flood of allegations of rape, sexual assault and abuse against Weinstein.
What was Weinstein accused of?
Reports published by The New York Times and The New Yorker in October 2017 revealed that dozens of women had accused film producer Harvey Weinstein of rape, sexual assault and sexual misconduct over three decades, with more than 80 women eventually coming forward.
Weinstein denied the accusations of non-consensual sex, but was soon fired from The Weinstein Company, expelled from professional associations and withdrawn from public life.
Criminal investigations began in Los Angeles, New York City and London. Weinstein was arrested in New York in May 2018 on rape and other charges.
In February 2020, Weinstein was found guilty of third-degree rape and sexual assault and sentenced to 23 years in prison. In addition, he was sentenced to another 16 years in prison for rape and sexual assault in Los Angeles in 2022.
The allegations against the once powerful and feared studio boss behind Oscar-winning works such as "Pulp Fiction" and "Shakespeare in Love" sparked the #MeToo movement.
Dozens of women, including famous actresses like Ashley Judd and Uma Thurman, have come forward and accused Weinstein.
Weinstein will remain in prison for his conviction in 2022. He is currently incarcerated at Mohawk Correctional Facility, about 160 kilometers northwest of Albany, New York.
Still maintaining his innocence, Weinstein claims that his sexual activities were consensual.
