Objective: Rare disease 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.