A third of the 1,165 young people have been bullied physically, have been frozen out or exposed to harassment.
"According to the survey 48 percent of pupils which have at some point felt exposed to bullying or offensive behaviour. It is unacceptable that so many experience school as an unsafe place," said Katarina Rosenqvist at Friends in a statement.
Rosenqqvist added that the survey, which is conducted annually, shows that there is much work to be done to counter bullying in schools.
"It is a clear sign that the work against bullying should be intensified," she said.
The survey showed that a fifth of school pupils would not dare speak up when they had been victims of bullying, and 30 percent did not know who they would approach at their school in any case.
"Aside from schools working more actively with everyday security factors, with conscious preventative measures, they have to involve pupils in this work. Pupil participation is a recognised success factor in getting rid of the problem," Rosenqvist explains.