Actinomycosis is a rare cause of a caruncular mass previously unreported in large clinicohistopathologic studies. A 25-year-old man presented with an enlarged and irritated left caruncle and an otherwise normal ocular examination. After the patient failed to respond to conservative medical management, an excision biopsy revealed an underlying diagnosis of actinomycotic granule of the caruncle. The patient's symptoms resolved, and after 6 months of follow up there was no evidence of recurrence. Actinomycosis is a slowly progressive, chronic infection with a nonspecific clinical presentation. Diagnosis is therefore difficult and is generally made on the basis of histopathology. This case demonstrates that actinomycosis can present as a caruncular mass.