Lentiviruses that infect non-primates make up a diverse collection of viruses. Although these viruses have some features in common with HIV and other primate viruses, differences in genome organization and viral gene function have made the successful derivation of vectors from non-primate lentiviruses unpredictable. This Chapter discusses the construction and application of gene transfer systems derived from four non-primate lentiviruses including equine infectious anemia virus (EIAV), caprine arthritis encephalitis virus (CAEV), visna virus, and Jembrana disease virus (JDV).