Court officials and lawyers said the court in Western Sahara's main town, Laayoune, announced the verdict early on Wednesday at the end of a 14-hour hearing.
Morocco annexed the former Spanish colony in 1975, claiming historic sovereignty rights over the mostly desert territory.
The move triggered a sporadic guerrilla war with the Polisario Front, which seeks an independent state in the mineral-rich territory.
A UN ceasefire was brokered in 1991 with the promise of holding a referendum to decide on the fate of the area, believed to have offshore oil deposits.
Disagreements between the two sides about who is eligible to vote have prevented it from taking place.
Morocco, steering away from the UN-sponsored referendum plan, recently stated its readiness to grant autonomy to the territory, but the Polisario rejected that and threatened to resume war if there is no breakthrough in the near future.
Polisario supporters led anti-Moroccan riots in May, leading to several arrests, including the 14 activists sentenced by the court on Wednesday.
Morocco annexed the former
Spanish colony in 1975
One of them, Mohamed Tahlil, who appeared in court wearing military fatigues to underscore his support for the Polisario, was jailed for three years while six other activists were sentenced to two years in prison, lawyers said.
The seven other activists were sentenced to between six months and 10 months in prison.This included female rights activist Aminatou Haider who was jailed for seven months.
The defendants were found guilty of charges including damaging public property, violence against government employees, belonging to an illegal organisation and gathering in the streets without proper permission, lawyers said.