The study, commissioned by internet safety charity Trast and the World Childhood Foundation, which was set up by Sweden's Queen Silvia, found that more than half of girls has been contacted.
“The numbers are extremely high, worryingly high, but it is a similar result to other surveys,” Gustav Alberius, Trast's founder, told The Local. “It's basically a fact that half of all girls are being contacted with sexual intentions online, which is crazy.”
The survey of 1,015 people aged between 16 and 20 years old asked if, before they were 15, anyone over the age of 20 had tried to talk to them about sex, sent them naked pictures of themselves or others, or asked if they wanted to meet, or do something sexual with them.
No less than 51 percent of female respondents answered 'yes' to one or more of these questions, 18 percent of boys, and 37 percent overall.
The survey has been released to coincide with Safer Internet Day 2018, an intitiative launched by the European Union in 2004.
Alberius said he hoped the survey result would highlight the scale of the problem.
“Our goal today is to try to shine a light on the fact that this problem is this big, and also to ask parents to try to be more active with their children, and engage with their children online.”
The survey found that the apps Snapchat, Kik, Instagram and Facebook were the ones most frequently used by suspected adults to contact children.
He said his charity was set next month to launch a digital tool which could be installed on children's phones, tablets or computers, which would challenge any new contact to identify themselves using Sweden's Mobile Bank-ID system.
If they refuse, the app will then send a message to the child's parent warning them that someone who refuses to identify themselves is chatting to their child.
He said that it was more effective for adults to monitor who was in contact with their children than to try to monitor the content of conversations, as the latter risked pushing their children to other, more private platforms.