Squamous cell carcinoma (SCC) is a malignant epidermal tumor. Biologic behavior and metastasis rate vary according to species and tumor location. The goal of this study was to report the occurrence and behavior of an oral SCC in a Tapirus terrestris treated with electrochemotherapy. The tapir was anesthetized for two electrochemotherapy sessions, six months apart, with intralesional cisplatin (0.25 mL/cm³) and VetCP 125^TM electroporator. Side effects were minimal. Because of tumor relapse, onset of joint disorders, and poor prognosis, the animal was euthanized and submitted to necropsy, followed by histopathological and immunohistochemical analyses. Electrochemotherapy significantly improved the tapiŕs life quality. Tumor bleeding resolved, and food uptake was improved. Necropsy demonstrated tumor invasion in adjacent soft tissues and bones and submandibular lymph nodes with multiple areas of metastasis. Overall survival time of 35 months was achieved, with good life quality. Histopathologic characteristics were more aggressive in the relapsed tumor.