Non-Hodgkin lymphomas include a biologically and clinically heterogeneous group of cancers distinguished by genetics, histology, and treatment outcomes. New discoveries regarding the genomic alterations and epidemiological exposures associated with these lymphomas have enhanced our understanding of factors that contribute to lymphomagenesis for specific subtypes. We explore the impact of normal B-cell biology engineered for recognizing a wide variety of antigens on the development of specific lymphoma subtypes, review lymphoma genetics, and examine the epidemiology of B-cell NHLs including recent investigations of risk factors for particular lymphoma subtypes based on large pooled analyses. Burkitt lymphoma, an aggressive form of B-cell NHL involving translocation of the MYC gene and an immunoglobulin gene has been associated with a history of eczema, hepatitis C, and occupation as a cleaner. Increased risk of diffuse large B-cell lymphoma has been associated with increased young adult body mass index, history of B-cell-activating autoimmune diseases, hepatitis C, and several single nucleotide variants involving the human leukocyte antigen (HLA) region of chromosome 6 and non-HLA loci near EXOC2, PVT1, MYC, and NCOA1. Tumor sequencing studies suggest that multiple pathways are involved in the development of DLBCL. Additional studies of epidemiological exposures, genome wide associations, and tumor sequencing in follicular, lymphoplasmacytic, marginal zone, and mantle cell lymphoma demonstrate overlapping areas of increased risk factors and unique factors for specific subtypes. Integrating these findings is important for constructing comprehensive models of NHL pathogenesis, which could yield novel targets for therapy and strategies for lymphoma prevention in certain populations.