Constitutional Court Decision On Administrative Fines Imposed Under The Personal Data Protection Law

The Constitutional Court (“Court”), in its decision dated 27 January 2026, bearing application number 2020/32193 (“Decision”), examined an administrative fine imposed under the Personal Data Protection Law No. 6698 (“DP Law”) in the context of the principle of legality in offences and penalties as guaranteed under Article 38 of the Constitution, and ruled that the said principle had been violated. The Decision was published in the Official Gazette dated 16 June 2026.

Decision is significant not only with respect to the specific dispute at hand, but also in terms of the legal basis of administrative sanctions imposed under the DP Law, the limits of the interpretive methods adopted in the decisions of the Personal Data Protection Board (“Board”), and the role of the guidance documents published by the Personal Data Protection Authority (“Authority”) in enforcement proceedings. Court emphasized that the imposition of an administrative sanction based on a concept not expressly