The prevalence of systemic lupus erythematosus (SLE) varies significantly based on ethnicity rather than geographic distribution; thus, the prevalence is higher in Asian, Hispanic, and Black African populations than in European populations. The risk of developing lupus nephritis (LN) is the highest among Asian populations. Therefore, we hypothesize that human genetic diversity between races has occurred through the early human migration and human genetic adaptation to various environments, with a particular focus on pathogens. Additionally, we compile the currently available evidence on the ethnic gene diversity of SLE and how it relates to disease severity. The human leukocyte antigen (HLA) locus is well established as associated with susceptibility to SLE; specific allele distributions have been observed across diverse populations. Notably, specific amino acid residues within these HLA loci demonstrate significant associations with SLE risk. The non-HLA genetic loci associated with SLE risk also varies across diverse ancestries, implicating distinct immunological pathways, such as the type-I interferon and janus kinase-signal transducers and activators of transcription (JAK-STAT) pathways in Asians, the type-II interferon signaling pathway in Europeans, and B cell activation pathway in Africans. Furthermore, assessing individual genetic susceptibility using genetic risk scores (GRS) for SLE helps to reveal the diverse prevalence, age of onset, and clinical phenotypes across different ethnicities. A higher GRS increases the risk of LN and the severity of SLE. Therefore, understanding ethnic gene diversity is crucial for elucidating disease mechanisms and SLE severity, which could enable the development of novel drugs specific to each race.