Cyclosporin A (CyA) is a potent immunosuppressor used in organ transplantation and in the management of various autoimmune diseases. Gingival overgrowth is one of the side‐effects of the CyA‐treatment, affecting the attached gingiva of 25–81% of treated patients. To investigate the production and activity of matrix metalloproteinases (MMPs) in the CyA‐induced gingival overgrowth, 2 well‐documented models were utilized: the in vivo CyA‐induced rat gingival overgrowth and primary cultures of human gingival fibroblasts treated with CyA. Our results obtained from the Western blot assays demonstrated clearly that the production of MMP‐1 and MMP‐3 was significantly inhibited by CyA at similar concentrations found in the serum of patients undergoing CyA‐treatment. Moreover, the gelatinolytic activity of MMP‐2 was also reduced both in cultured fibroblasts and in the rat CyA‐induced gingival overgrowth. Taken together, the data presented here suggest that these inhibitory effects may contribute to the extracellular matrix (ECM) components accumulation in the CyA‐induced gingival overgrowth.