Plasma cell mucositis (PCM) is a rare benign proliferative disorder affecting various mucosal surfaces usually seen in elderly patients. In the present case, a 13-year-old young boy reported with the complaint of swollen upper lip and enlarged gums in relation to upper front teeth. The diagnosis of plasma cell mucositis is complex and frequently requires histopathological examination and immunohistochemistry. Management included conventional gingivectomy and intralesional steroid. Regular follow-up of PCM is essential based on the possibility of recurrence, the potential involvement of other mucosal surfaces and unknown potential for malignant transformation.