BACKGROUND Trauma to the left submandibular gland is an infrequent entity, with only a few cases reported in the literature. Recommended management consists of excision of the gland if trauma is suspected; if trauma is not clearly identified during the surgical exploration and the gland is not removed, post-traumatic complications such as fistula or sialocele may occur. In such cases, conservative measures including aspiration, pressure bandages, and anti-sialogogues are the first step of treatment and surgical excision is reserved for unsuccessful cases. CASE REPORT This report describes a case of post-traumatic surgical emphysema and sialocele with fistula following knife wounds to the head and neck of a 30-year-old woman. The patient had an incised wound to the left submandibular gland. Subsequently, a painful slow-growing mass developed and the diagnosis of sialocele was considered. Confirmation of this diagnosis was achieved by performing a fine-needle aspiration, which revealed a high amylase level within the collection. Afterwards, pressure bandages were applied and no recurrence of the sialocele was observed in imaging follow-up. CONCLUSIONS This report shows that although submandibular gland trauma is rare, it can lead to salivary fistula or sialocele. The diagnosis of sialocele can be confirmed by imaging combined with fine-needle aspiration and measurement of amylase levels in the aspirate. Identification of traumatic sialocele and fistula at an early stage will lead to the most appropriate management.