Splenic marginal zone lymphoma (SMZL), along with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) and nodal marginal zone lymphoma (NMZL), share a common origin from the "marginal zone." However, these three entities display different clinical characteristics, reflecting probable biological variations according to the organ and cellular origin. Within the past decade, new data have been reported regarding pathogenic mechanisms as well as therapeutic advances. Clinically, SMZL presents as an indolent and disseminated disease at diagnosis, with a specific clinical presentation that includes predominantly splenomegaly, and in half of patients, autoimmune manifestations. Establishing the diagnosis may be difficult, especially distinguishing SMZL from other low-grade lymphomas, such as small B-cell lymphomas; however, recent findings have contributed to a better characterization of the disease, and the criteria for diagnosis have been improved. Therapeutic approaches consist of splenectomy or immunochemotherapy, but there is no consensus regarding the best treatment, except when SMZL is associated with hepatitis C virus infection. In this article, we review the current knowledge on the biological findings, clinical features, and therapeutic approaches for SMZL.