The 90210 star was hosting an event for the Somaly Mam Foundation, which aims to end slavery and human trafficking, Us Weekly reports.
McCord, who was supported by her 90210 co-stars at the event, told the audience: "Has anyone ever been raped? Sexually abused? Not said 'no' when you felt you didn't have the right to? I know what it feels like."
Later, the actress told Us that she "had a very similar experience to what these girls go through 20 times a night".
"It happened to me once by somebody that I knew, and it is a very interesting thing to feel that you do not have the voice to say 'no'," she said. "It wasn't an attack or anything like that - I just had no voice. I did not know how to say, 'I don't want this. Please do not do this to me'."
McCord added that she wants to speak out on behalf of people who have been through similar experiences.
"It was a situation where I found myself in my own home being hospitable, and that hospitality was taken advantage of at an extreme level," she said. "I did not have a voice, and now I do, and I'm practising using my voice for others.
"Finally I can say I was taken advantage of - not from my own shame that I did something to deserve that - and now I can have a clear conscience."