c-MYC is one of the most essential transcriptional factors, regulating a diverse array of cellular functions, including proliferation, growth, and apoptosis. Dysregulation of is essential in the pathogenesis of a number of B-cell lymphomas, but is rarely reported in T-cell lymphomas. dysregulation induces lymphomagenesis by loss of the tight control of expression, leading to overexpression of intact c-MYC protein, in contrast to the somatic mutations or fusion proteins seen in many other oncogenes. Dysregulation of in B-cell lymphomas occurs either as a primary event in Burkitt lymphoma, or secondarily in aggressive lymphomas such as diffuse large B-cell lymphoma, plasmablastic lymphoma, mantle cell lymphoma, or double-hit lymphoma. Secondary changes include gene translocation and gene amplification, occurring against a background of complex karyotype, and most often confer aggressive clinical behavior, as evidenced in the double-hit lymphomas. In low-grade B-cell lymphomas, acquisition of rearrangement usually results in transformation into highly aggressive lymphomas, with some exceptions. In this review, we discuss the role that c-MYC plays in the pathogenesis of B-cell lymphomas, the molecular alterations that lead to dysregulation, and their effect on prognosis and diagnosis in specific types of B-cell lymphoma.