Tapirs are endangered terrestrial mammals that inhabit several continents. They have anatomical similarities to horses, sharing a common ancestral lineage. This article reports the case of a 14-yr-old female lowland tapir (Tapirus terrestris) presented for intermittent lameness due to upward fixation of the patella causing extension of the limb in the caudal phase of the stride. Medial patellar desmotomy was performed under general anesthesia, correcting the problem. To date there are no reports of this condition or treatment recommendations in tapirs. An anatomical study including stifle dissection, advanced MRI, and CT was performed in a separate lowland tapir. According to the clinical case and the anatomical findings in the other lowland tapir, upward fixation of the patella may occur in the tapir, although the anatomy varies slightly from that of the horse. Because the lowland tapir does not have parapatellar cartilage or as large of a medial patellar ligament or medial trochlea of the distal femur compared to the horse, more severe disease secondary to complete or persistent upward fixation of the patella may not occur in tapirs. Rather, mild forms of the disease associated with intermittent upward fixation of the patella or delayed patellar release appear more likely in the tapir.