McGowan, delivering opening remarks at The Women's Convention in Detroit, thanked the audience "for giving me wings during this very difficult time."
"The triggering has been insane, the monster's face has been everywhere, my nightmare," she said.
"I have been silenced for 20 years. I have been slut- shamed, I have been harassed, I have been maligned, and you know what? I am just like you. What happened to me behind the scenes happens to all of us in this society. It cannot stand and will not stand."
On Twitter, McGowan has amassed supporters and urged them to call out harassment using the #RoseArmy hashtag. McGowan has starred in several films, including "Scream," ''Jawbreaker," and "Planet Terror," as well as the early 2000s television series "Charmed."
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Weinstein was fired from The Weinstein Company on October 8 after The New York Times published an expose that detailed decades of sexual harassment allegations against him. The Oscar-winning producer apologized without addressing any specific conduct, but has denied later allegations by several women that he raped them.
On Friday, McGowan said because Hollywood is male- dominated, "we are given one view." She said the entertainment industry isn't isolated; instead, "it is the mirror you are given to look into."
"I know the men behind that view. They shouldn't be in your mind and they shouldn't be in mind. It's time to clean house."
Weinstein representative Sallie Hofmeister has denied all allegations of non-consensual sex.
He sued his former company on Thursday, seeking access to email and personnel records his lawyer contends would exonerate him.