SummaryBrazilian hair sheep constitute a genetic diversity hotspot. These animals are found in the harsh environments of the Brazilian Northwest (semi‐arid) region. Genotypes (50K SNP chip) from seven Brazilian sheep breeds (five hair and two coarse wool types) and 87 worldwide breeds were used to test for population structure, admixture and genetic diversity. Moreover, phylogenetic trees evaluating migration events between genetic groups were built. Brazilian Somali, a fat‐tailed breed, had a close relationship with East African breeds and clustered distinctly from other Brazilian breeds. Brazilian Blackbelly and Barbados Blackbelly had a close relationship. The Morada Nova breed did not show close relationships with European or African breeds, revealing a single migration event from an Algerian hair breed. Brazilian Fat‐tail and Morada Nova share a common ancestor, but the former showed introgressions from Brazilian Somali and Afrikaner breeds, explaining the fat‐tail phenotype. The Santa Inês breed received a substantial contribution from Brazilian Bergamasca and showed an admixed origin with recent introgressions from other breeds, mainly from Suffolk. Furthermore, Brazilian Somali and Brazilian Fat‐tail are the most endangered sheep genetic resources in Brazil and should be the focus forex situconservation programs. In conclusion, Brazilian hair sheep show an African origin and are characterized by diverse genetic composition, reinforcing the need for conservation of these genetic resources, and at the same time, this highly diverse group has variability that can be used in breeding programs.