The investigation of Campanula L. (Campanulaceae) plants in the eastern Black Sea Region of Turkey revealed three new Mecinini weevil species/host plant associations: Miarus ajugae (Herbst, 1795) with Campanula lactiflora Bieb., Cleopomiarus distinctus (Boheman, 1845) with Campanula alliariiafolia Willd. and Campanula rapunculoides L., and Cleopomiarus caucasicus Caldara and Legalov, 2016 with Campanula trachelium L. Of these weevil species, M. ajugae and C. caucasicus are new records for the fauna of Turkey. All three weevil species deposit their eggs in the ovary of the flowers and larvae feed on young seeds, where they pupate when mature.