Actors have hailed a widening of roles for women - including reports of a female 007 in next James Bond film - but sexism is still rampant, according to rights group Plan International and the Geena Davis research institute.
Female leaders were four times more likely to be shown naked on screen than similar male roles, they found, after studying the 56 top-grossing films of 2018 in 20 countries.
"A woman 007 or superhero in film is welcome. But our research shows they are exceptions and not the rule," said Anne-Birgitte Albrectsen, chief executive of Plan International.
"The bigger picture is that gender discrimination and harmful stereotypes still dominate on screen ... We need to stop the sexualisation and the objectification of women and girls on screen and everywhere else."
Women are still under-represented on screen, according to research by San Diego State University, which found they were often relegated to supporting roles, and only one in three speaking characters in top-grossing films of 2018 were female.
But even when they do appear in powerful roles, they are often objectified, according to the new study, which used machine learning to examine 56 top films in countries from United States to India, Sweden, Uganda and South Sudan.
It found that nearly a third of powerful female characters were shown wearing revealing clothing compared to less than 10% of similar male characters.
Women bosses were four times more likely to be shown completely naked, at 2% compared to 0.5%.
The report also highlighted the prevalence of men behind the camera. None of the films analysed in the report was directed by a woman, and only 10% had at least one woman among its writers.
"Girls need to see themselves reflected on screen and to see positive and authentic characters that can inspire them," said Geena Davis, the Oscar-winning star of "Thelma and Louise" who set up the institute to address harmful gender stereotypes.
"Content creators and storytellers in entertainment and media have an opportunity to support and influence the aspirations of girls and women and stop reinforcing damaging gender stereotypes."
