The term marginal-zone lymphoma (MZL) encompasses three closely related indolent B-cell non-Hodgkin's lymphoma subtypes, namely extranodal MZL or MALT lymphoma, nodal MZL, and splenic MZL. Although these neoplasms may share a common cell of origin, being the marginal zone B-cell, they display different characteristics with evident clinical and biological variations according to the organ where the lymphoma arises. The past 2 decades have spawned an avalanche of new data that encompasses the genetic aberrations and pathogenic mechanisms leading to these diseases. This article briefly addresses each of the MZL.