Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of B-cell lineage lymphoma that can affect the head and neck region. This report presents a rare case of an extra-nodal marginal zone B-cell MALT lymphoma of a sublingual gland, diagnosed in an 18-year-old male patient. The patient had a history of ranula surgical removal on the right side of the mouth. One year after surgery, the patient presented with complaints of swelling of the left parotid gland, with no significant changes found during the examination and a self-resolving outcome. Subsequently, two years later, the patient began to complain of a fast-growing cyst under the tongue. A surgical excision of the left sublingual gland and the ranula was performed, and a final diagnosis of MALT lymphoma was rendered. The patient was referred to the department of hematology for further treatment planning and follow-up.