It is not yet clear when Aydin C. will be extradited to Canada, as the Dutch justice ministry now has to set a date.
"The appeals court rejects the request," the judges said in a statement. The man has only been identified as Aydin C. due to strict Dutch privacy laws.
Dutch authorities agreed in June he could be extradited to Canada, where he is wanted on charges linked to the death of 15-year-old Amanda Todd, after his trial in The Netherlands.
Arrested in 2014 after Facebook alerted the Dutch police, he was found guilty of harassing dozens of young girls and women from as far away as Britain, Canada, Norway and the United States.
He was sentenced last month to almost 11 years in jail, after being found guilty of 72 charges including computer sex crimes such as making and storing child pornography, as well as extortion, fraud and hard drug possession.
Todd committed suicide in October 2012 after being tormented by an anonymous cyberbully. Before killing herself, she posted an online YouTube video in which she detailed the abuse written out in felt-pen on a series of flashcards.
It is not yet clear when Aydin C. will be extradited to Canada, as the Dutch justice ministry now has to set a date. He may also yet appeal his first conviction.
Todd's mother Carol flew from British Columbia to The Netherlands to attend part of Aydin's trial earlier this year.
He is suspected of having persuaded Amanda Todd to expose her breasts via her computer's webcam and putting a photo online after she refused to do it again.
Her suicide triggered an outcry in Canada and a debate about the dangers of cyberbullying.