Girls as young as seven experience routine sexual harassment, according to leaders of the Girlguiding Association.
The claims were based on the Guides' annual Girls' Attitudes Survey, a poll of opinions of girls aged between seven and 21.
It said sexual harassment is a normal part of girls' lives and that girls as young as seven experience sexual taunting from boys.
Half of the girls aged between 11 and 16 who took part said that teachers and staff at their schools dismiss harassment as banter or tell them to ignore incidents.
Seven out of 10 girls aged between 13 and 16 said that those who report incidents risk being bullied or teased.
The findings were made public by Girlguiding Scotland which called for a response from politicians.
Chief Denise King said: "This shocking research shows we must act to stop sexual harassment being normalised by our society.
"We want to ensure all girls live in a safe, fair and equal society that lets them reach their full potential. We're calling on all politicians to take a stand."
The call follows the launch by Girlguiding in England of a feminist election manifesto which demands compulsory school lessons in 'body confidence' and equal numbers of men and women in Parliament.
The movement added that 'young women still believe they are too often treated like second-class citizens' and that there is 'overwhelming evidence of inequality for girls in the UK'.
The survey results showed that one in five girls from seven to 12 say they have been subjected to harrassing of a sexual nature from boys.
Overall, it said, one in five girls aged 13 to 21 had experienced unwanted sexual attention or unwanted touching.
Guide Amy Callaghan, 16, part of the panel that developed and analysed the research, said: "Every day, many girls' lives are made a misery by sexist comments, sexual harassment and abuse at school.
"What's worse is that it's not being treated as a serious issue. We need politicians to take action and sign up to our Girls Matter pledges. We need them to send a message that this kind of behaviour towards girls and young women will not be tolerated."
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