A north Cairo military court acquitted 14 Qoursaya Island residents and convicted a further 12 on charges of assaulting the military and seizing land owned by the armed forces.
The charges relate to a dispute between the residents of the island, located close to central Cairo, and the military, which claims ownership of the island.
The court sentenced 11 residents to three months in prison, and one resident to five years in prison.
The residents were arrested on 18 November during clashes between military police and island residents.
A spokesman for the military said in November that the land in question was the property of the armed forces, which needed it for military exercises aimed at "securing the capital."