Bony exostosis (BE) is described as a benign localised overgrowth of bone of unknown aetiology. Buccal bony exostosis (BBE) development secondary to soft tissue graft procedures has been reported in a small number of cases. The dental literature describes BBE development also at sites where free gingival grafts (FGG) have been used to increase the amount of gingiva. The following case series describes BBE development at nine sites (five cases) at which FGG was performed to increase the width of the attached gingiva. The presence of exostoses has been recognised during postoperative visits. Histological examination revealed osseous enlargements compatible with the diagnosis of exostoses at two re-entry procedures. In conclusion, based on previous reports, periosteal trauma, eg fenestration, seems to be the main aetiologic agent associated with the development of BBE in areas where FGG were placed.