The 1965–66 Turkish Cup was the 4th edition of the annual tournament that determined the association football Süper Lig Turkish Cup (Turkish: Türkiye Kupası) champion under the auspices of the Turkish Football Federation (Turkish: Türkiye Futbol Federasyonu; TFF). Galatasaray successfully contested Beşiktaş 1–0 in the . The results of the tournament also determined which clubs would be promoted or relegated.