Some 20% of teenage girls have been hit by their boyfriends, a survey by children's charity the NSPCC suggests.
The responses of 2,000 teenage girls were analysed for the survey
It found 4% were subjected to regular attacks by their partner and a further 16% had been struck at least once.
And 31% believed it was acceptable for a boy to act in an "aggressive" way if his girlfriend had cheated on him.
The NSPCC said the survey of 2,000 teenage girls, carried out with teen magazine Sugar, revealed "a real issue about self-worth" among teenage girls.
"This survey reveals a generation of girls, many of whom are growing up believing that aggression is an acceptable part of life," spokesman Wes Cuell said.
The NSPCC said the figures were particularly worrying because they revealed a clear link between girls experiencing domestic abuse at home and then getting abused by boyfriends.
Almost one out of every three - 31% - of girls who were hit regularly by their boyfriends had seen their parents hit each other.
Mr Cuell, who is the charity's director of services to children and young people, said it was vital children who were being abused sought help.
More than two out of every three of the girls hit by boyfriends stayed with them, and one out of every five ignored the abuse altogether.
The responses of 2,000 teenage girls to a questionnaire carried in Sugar magazine and on its website in January were analysed for the survey.
Some 6% of the girls aged between 13 and 19, whose average age was 15, had been forced to have sex by a boyfriend.
And one out of every three of them forgave and stayed with him.
Sugar editor Annabel Brog said: "This survey paints a frightening picture of domestic violence and the link between girls seeing abuse at home and then going on to be hit by a boyfriend themselves.
"An appalling number of girls feel that violence at home or in relationships is sometimes acceptable."