The incident occurred in Kristianstad and sparked a court action against the teen.
His teacher had asked him to leave the room for disturbing the class and in response the boy approached her and said he wanted to give her a hug.
However, instead of embracing his teacher he proceeded to pull down his pants and pressed himself against her. The boy then began slowly fondling her breasts reported the Metro newspaper.
"He turned to the class and said 'there, I scored' and laughed," the teacher said.
The distraught teacher immediately brought the class to an end. She said in a police interview that she broke down and began crying after the assault.
In court the boy admitted to hugging his teacher but denied the assault charge.
He was subsequently convicted in court to a number of day-fines and to pay the teacher more than 18,000 kronor ($2700) in damages jointly with his parents.
In the judgement released by the Kristianstad district court they said the teacher's story was credible and that she had experienced something which "clearly deviated from friendly hugs."
The boy was suspended following the incident and has since switched to another school.