Plasma cell gingivitis (PCG) is an infrequent inflammatory disease of the gingiva of unknown etiology, characterized by a dense polyclonal proliferation of plasma cells in the connective tissue. The aim of this study was to present a case series of patients affected by PCG, analyzing demographic, clinical, histopathological, and therapeutic data. A group of 36 females and 9 males with a mean age of 60.3 years was evaluated. Clinically, 25 cases were bullous, a clinical phenotype never reported to date, 4 erythematous, 4 keratotic, 4 verruciform, and 3 ulcerative. On histological examination, pure polyclonal plasma cell infiltrate was detected in 20 specimens, while in 25 specimens it was associated with a mixed infiltrate. The first-line therapy consisted of oral hygiene and topical corticosteroids in all patients. In 25 patients, doxycycline and sulfasalazine were added; in 10 of these patients, the disease persisted, and it was necessary to resort to systemic steroids. This study presented the clinico-pathological profile and outcomes of a case series of PCG. This could be an aid for clinicians to be aware of the heterogeneous clinical phenotype and of the possible pure bullous phenotype of PCG. Further studies are needed to improve the knowledge about this disorder.