The producer and film executive was fired from his own company on 8 October, following the publication of a report which accused him of sexually harassing female employees, actresses and journalists.
Directors of The Weinstein Company said "in light of new information about misconduct" his employment had been terminated "effective immediately".
The New York Times, which published the original story about the allegations against the movie mogul, also published a scathing piece about how major entertainment figures had refused to go on the record to criticise Weinstein.
Rose McGowan, one of the actresses who settled with Weinstein, wrote on Twitter last week: "Ladies of Hollywood, your silence is deafening."
Apatow criticised Weinstein's statement in response to the allegations, which claimed he "came of age in the 60's and 70's, when all the rules about behaviour and workplaces were different".
The director tweeted: "The 70's were 37 years ago. You are blaming growing up in the 70's? You haven't picked up anything since then?"
Chastain, who has posted and retweeted several updates on the Weinstein case, wrote on 6 October: "Women are fighting against the 'Grab Them By The Pussy' normalisation & speaking up. It's never easy to be the first to go on record #Respect."
Dunham said: "The woman who chose to speak about their experience of harassment by Harvey Weinstein deserve our awe. It's not fun or easy. It's brave."
Amber Tamblyn tweeted: "Stand with @AshleyJudd or give your legs to someone else. What she and others have just done is painful and difficult and triumphant."
Allegations against Weinstein include asking a British journalist to have a bath with him at his hotel when she arrived for a business meeting, and masturbating in front of a former Fox News reporter after cornering her in a restaurant.
In a statement to the New York Times he said: "I appreciate the way I've behaved with colleagues in the past has caused a lot of pain, and I sincerely apologise for it. Though I'm trying to do better, I know I have a long way to go."
Lisa Bloom, a lawyer acting for the producer, said he "denies many of the accusations as patently false". She has since resigned as his adviser following criticism given her past work with victims of sexual harassment, including from her mother, Gloria Allred.
Weinstein's removal from The Weinstein Company will leave it in the control of his brother, Bob Weinstein, along with chief operating officer David Glasser.
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