Five of the teens were found guilty of aggravated rape by the Solna District Court on Friday, with the sixth guilty of attempted aggravated rape.
The attack took place in early March at an apartment in Tensta, where one of the teens dealt out condoms while the other five took turns raping the 15-year-old girl.
The court took into account that the girl's information included "a cohesive, long, and relatively detailed account" of the incident that did not contain "any contradictions or elements to the story that could be considered inexplicable".
Despite denying the incident occurred when the trial opened, four of the boys have since confessed to having had intercourse with the girl at the time, but have denied committing any crime. The boy who allegedly provided the condoms has denied everything.
"According to the court, their explanations as to why they've changed their story are not sustainable, but suggest that they're trying to hide something," the court wrote, according to the TT news agency.
Five of the boys have been sentenced to over 100 hours of community service each, and have been ordered to pay 55,000 kronor ($8,500) each in damages to the victim.
The punishment was less severe than it could have been as the boys are minors, and the court also concluded that they had already been punished to some extent by having their pictures and their personal details exposed on the internet.
The case was the third suspected gang rape to take place in the Stockholm area earlier this year. In January, three men, two of whom were teenagers, were ordered held on remand on suspicion of raping a woman in central Stockholm in December.
Also that month, a woman reported being attacked and raped by five men in Sundbyberg, just west of Stockholm.