Those on trial on Monday include prominent journalist Nazli Ilicak, former newspaper chief editor Ahmet Altan and his brother Mehmet Altan, an economics professor and writer. They are accused of having prior knowledge of the coup attempt and of supporting it.
Turkey blames U.S.-based cleric Fethullah Gulen and his movement for the coup attempt. Gulen has denied involvement.
Ilicak and the Altan brothers are among six jailed defendants. Ten other suspects, including Ekrem Dumanli, the former editor-in-chief of the Gulen-linked Zaman newspaper, are at large and being in absentia. Another defendant is free.
More than 100 separate trials linked to the July 15 failed coup are currently underway.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.