Leiomyomas are uncommon in the oral cavity and rare on gingiva. They account only for 0.42% of all soft tissue lesions in the oral cavity. We present an extremely rare case of leiomyoma localized to the attached gingival, simulating an epulis in a healthy 14-year-old boy. The tumour was described at the clinical and instrumental level; moreover, its histopathological phenotype was depicted. The treatment of the choice was the radical excision. The wound was closed by surgical dressing with 2-0 silk suture.The post-operative course was uneventful. The surgical wound healed in one week with normal scarring. Finally, the problems of differential diagnosis with other tumours of the oral cavity and the most appropriate therapeutic procedures are discussed.