"When I was a teenager, I was attacked on a train … I remember at the time being so angry," she said during a discussion broadcast on Wednesday about violence against women.
"I was reading my book and you know this boy - man - attacked me, and I did fight back."
She said she did not know the man who attacked her.
Camilla, 78, has for many years championed charities and causes that seek to end sexual and domestic violence and to support victims.
The assault was first reported in September when a book about the royal family was serialised in the Times newspaper, but had not previously been confirmed by Buckingham Palace.
"I remember getting off the train and my mother looking at me and saying 'Why is your hair standing on end and why is the button missing from your coat?'" she told the BBC.
"I was so furious about it and it's sort of lurked for many years."
The book said the incident happened on a train to Paddington Station in London when Camilla was about 16 or 17 years old, and she responded by taking off her shoe and using it to hit him in the genitals.
When she arrived at Paddington, she pointed the attacker out to an official and he was arrested, the book said.
Camilla did not confirm those details in the interview.
The Queen is the second wife of King Charles, who ascended the throne in 2022.
