Canadian Sikhs should be allowed to wear small daggers central to their faith when they go to school, the country's Supreme Court has ruled.
Gurbaj Singh Multani was aged 12 when the controversy erupted
In an 8-0 judgement, the court reversed the ruling of a Montreal school board, which banned Gurbaj Singh Multani from wearing his dagger, known as a kirpan.
The kirpan is deemed sacred by Sikhs as a symbol of power and truth.
School authorities banned the kirpan in 2001 after an objection by a parent concerned about pupil security.
Announcing the judgement, the Supreme Court said that a total ban on kirpans violated the country's Charter of Rights.
The charter guarantees total religious freedom within Canada.
"Religious tolerance is a very important value of Canadian society," Justice Louise Charron wrote in the judgement.
"If some students consider it unfair that Gurbaj Singh may wear his kirpan to school, it is incumbent on the schools to discharge their obligation to instil in their students this value that is... at the very foundation of our democracy."
The government of Quebec had backed the Montreal school board, which imposed the ban.
Parents campaigning for tighter restrictions on weapons in school were dismayed by the ruling.
"My first reaction as a parent is a feeling of insecurity," Claude Bouchard of the Quebec Federation of Parents' Committees, told Reuters news agency.
"As a parent, is the life and safety of a child more important than religious freedom? I think so."
The ruling did allow some restrictions to be imposed on kirpans worn in public, including limiting their length and keeping them sheathed and worn underneath clothes.
Nevertheless, Gurbaj Singh Multani, who was 12 when he was suspended and then removed from his school, welcomed the judgement.
"Everybody stood for their rights. I got it. I'm happy," he said outside the court.
Orthodox Sikhs have been required to carry kirpans since the 17th century, and insist it is not a weapon.
About 250,000 Sikhs live in Canada, with 10% considered orthodox.