The Anatolia news agency said the duchess, better known in Britain as Sarah Ferguson or simply as Fergie, is accused of violating the privacy of five children when she filmed with a hidden camera at an orphanage outside Ankara in 2008.
Britain has already rejected a 2009 request from Ankara for the duchess's extradition. The documentary, screened on Britain's ITV1 television channel in November 2008, depicts disturbing scenes at the orphanage for handicapped children, including one where a child is seen encased in a wooden box.
Turkish prosecutors are seeking a prison term of between seven and a maximum of more than 22 years. No date has been set for any trial.
Ankara has accused Ferguson of malice and trying to stain Turkey's reputation as the country tries to gain entry into the European Union.