An "alarmingly high" number of girls and young women feel unsafe outside their home, according to annual research for Girlguiding UK.
The survey of 1,903 13 to 21-year-olds in the UK found nearly two-thirds either felt unsafe, or knew someone who was fearful walking home alone.
More than half had suffered harassment, or knew someone who had, it said.
But girls are responding more robustly than before and were also more likely to call themselves feminists, it said.
The research, the tenth over as many years, found more girls claim to understand what feminism means, with almost half saying they are feminists - up from a third in 2013.
One young woman, from the 11 to 16-year-old age group, told researchers a feminist was "a person who strongly believes in gender equality and that everyone no matter their background should be treated equally."
Another, aged between 17 and 21, described feminism as "equal rights and opportunities between men and women in the workplace, education and society".
The researchers said they felt the increased understanding of gender equality and equal rights was down to recent intense media coverage of these areas.
Perhaps linked to this greater awareness was the suggestion that fewer girls expected to encounter equality in all areas of life this year than in 2009.
And more girls and young women say they are seeing or experiencing sexism across all areas of their lives.
The researchers said: "It might mean they are more aware of it in the media, online and in public - the result of campaigns like #MeToo and #TimesUp.
"However, it is also possible it may reflect an increase in the scale of sexism for girls."
Compared to three years ago, more girls aged seven to 10 think the way people treat girls and women is affected by "naked pictures of women in the media, jokes about girls and more attention given to women's clothes than actions".
But there were also very real concerns about girls' safety.
One young woman aged between 11 and 16, said: "One thing that would improve girls' lives would be to make it safe for girls to walk down the street alone."
Another, aged 17 to 21, said: "Girls' lives would be better if things like harassment and stalking were taken seriously and punished properly."
The survey also found that an increasing number of girls have experienced unkind, threatening and negative behaviour online compared to five years ago.
But, it added: "Girls are more likely to ignore abuse and report it more, as well as delete posts."