The aim of this study was to determine the frequency and the mechanism of submandibular gland (SMG) involvement in oral cavity squamous cell carcinomas (OCSCC), and to discuss the necessity of extirpation of the gland. The authors investigated and analyzed the retrospective charts of 236 patients who underwent surgery for OCSCC over a 10-year period and the pathology reports of 294 neck dissections with SMG removal. SMG involvement was evident in 13 cases (4%). Eight cases were due to direct invasion, which was the most common mechanism. Four cases had infiltration from a metastatic periglandular lymphadenopathy, and in 1 case, metastatic disease was confirmed. The tongue and floor of the mouth were the most frequent primary sites associated with SMG involvement. The study found no bilateral cases, and in 135 SMG specimens benign pathologies were detected. Involvement of the SMG in OCSCC is not frequent. It is appropriate to preserve the gland unless the primary tumour or metastatic regional lymphadenopathy is adherent to the gland.