IgG4-related disease (IgG4-RD) is a fibroinflammatory, immune-mediated condition that results in tumor-like sclerosing lesions. Initially identified in patients with sclerosing pancreatitis and elevated IgG4 levels, this condition was primarily diagnosed based on histological findings, including a dense lymphoplasmacytic infiltrate with a high percentage of IgG4-positive plasma cells, extensive storiform fibrosis, and obliterative phlebitis, which can progressively impair organ function. Contemporary diagnostic guidelines stress the importance of correlating clinical, laboratory, imaginologic, and pathologic data to make an accurate diagnosis. The head and neck region is the second most frequent site for IgG4-RD involvement, and the oral cavity can also be affected. IgG4-RD is more commonly reported in middle-aged to elderly individuals, with a female predominance. Oral lesions are typically asymptomatic and may range in color from normal to reddish or red-purple. They are often rubbery to soft in texture and more frequently affect the palate, where they may present as unilateral or bilateral swellings. The jaw bones and the tongue are also affected sites. IgG4-RD can follow an indolent course or, alternatively, lead to significant morbidity. Corticosteroids remain the first-line treatment, typically resulting in rapid improvement of the lesions in most cases.