Turkey’s Constitutional Court has ruled that the conviction of a woman accused of membership in the Gülen movement violated the principle of legality in criminal law, saying the acts cited by lower courts did not clearly establish a criminal offense.
According to a decision dated January 6, 2026, recently made public, the court reviewed the case of Gülcan Çelik, who had been convicted of membership in the faith-based Gülen movement.
The ruling found a violation of Article 38 of Turkey’s constitution, which guarantees the principle of legality in criminal law. The court ordered that the case be sent back to a lower criminal court for retrial to remedy the violation.
Turkish President Recep Tayyip Erdoğan has targeted followers of the Gülen movement, inspired by the late Muslim cleric Fethullah Gülen, since corruption investigations in December 2013 implicated him as well as some members of his family and inner circle. He dismissed the probes as a Gülenist conspiracy and later designated the movement a terrorist organization in May 2016, intensifying a sweeping crackdown after a failed coup attempt in July of the same year that he accused Gülen of orchestrating. The movement denies involvement in the coup attempt or any terrorist activity.
Çelik’s conviction was based on several factors cited by prosecutors and accepted by the lower courts.
These included allegations that she supervised student housing linked to the movement between 2009 and 2012, worked for about three years as a teacher at a private educational institution said to be affiliated with it, was a member of a union alleged to have ties to the network and had engaged in transactions with Bank Asya, a bank linked to the movement.
Witness statements were also cited as part of the evidence against her.
Lower courts evaluated these elements together and ruled that they demonstrated membership in the organization.
The Constitutional Court, however, said the acts cited in the case did not sufficiently establish the “continuity, intensity and diversity” of activities required to prove membership in an illegal organization under Turkish law.
The court also said it had not been shown that the actions attributed to Çelik would reasonably have been understood by her as conduct that could lead to criminal liability.
For those reasons, the court ruled that the conviction violated Article 38 of Turkey’s constitution, which guarantees the principle of “legality of crimes and punishments,” meaning that individuals can only be punished for acts that were clearly defined as crimes under the law at the time they were committed.
It said a retrial would be sufficient to address the breach. The court rejected Çelik’s request for material damages, citing insufficient documentation, but ruled that she should receive compensation for non-pecuniary damages.
