The 41-year-old star hoped the Harvey Weinstein scandal will encourage women to speak up about harassment, reported People magazine.
"This has been a really hard week for women in Hollywood, for women all over the world, and a lot of situations and a lot of industries are forced to remember and relive a lot of ugly truths," Witherspoon said during her speech at the Elle Women in Hollywood.
Dozens of women have come forward to allege Weinstein, a heavyweight Hollywood studio head, of sexual assault and in some cases rape.
"(I feel) true disgust at the director who assaulted me when I was 16-years-old and anger at the agents and the producers who made me feel that silence was a condition of my employment. And I wish that I could tell you that was an isolated incident in my career, but sadly it wasn't. I've had multiple experiences of harassment and sexual assault and I don't speak about them very often."
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"I have just spoken to so many actresses and writers, particularly women, who have had similar experiences and many of them have bravely gone public with their stories. That truth is very encouraging to me and everyone out there in the world because you can only heal by telling the truth."
The actor-producer hoped that there would be a "new normal" where women have other women's back.
Her comments come after dozens of women have come forward to accuse Weinstein of sexual misconduct including Cara Delevingne, Ashley Judd, Gywneth Paltrow and Angelina Jolie.