Primary testicular lymphoma is a rare clinically aggressive form of extranodal lymphoma and is most frequently a diffuse large B-cell lymphoma by histology, but rare subtypes are clinically important accounting for a minority of all lymphoma cases and must be recognized. Non-Hodgkin’s lymphoma (NHL) as a primary testicular neoplasm accounts for approximately 9% of all testicular malignant tumors and 1–2% of all NHL. The median age at the time of presentation is 60 years, and the incidence of bilaterality varies from 6% to 38%. We present a case of a unilateral primary testicular mantle cell lymphoma of the testis. This report contributes to the growing understanding of the histologic heterogenicity of lymphomas including those arising in the testis.