Rosai-Dorfman disease (RDD) is a rare, non-neoplastic histiocytosis most commonly characterized by painless, massive cervical lymphadenopathy. Over half of all patients with lymph node involvement also demonstrate extranodal disease, with most affected individuals exhibiting lesions within the region of the head and neck. Oral manifestations of RDD are extremely rare, and almost always identified in association with nodal or other extranodal disease. However, rare examples of extranodal RDD, including oral RDD, without clinical or radiographic evidence of concomitant lymph node involvement, have also been described. We report a rare case of solitary, extranodal RDD arising within the mandible in a pregnant woman. To our knowledge, this case represents only the fourth documented example of solitary oral RDD. A review of the clinical and histopathologic features associated with RDD is also presented.