The Maasai are a Nilotic ethnic group inhabiting northern, central and southern Kenya and northern Tanzania. They are among the best-known local populations internationally due to their residence near the many game parks of the African Great Lakes and their distinctive customs and dress. The Maasai speak the Maa language (ɔl Maa), a member of the Nilotic language family that is related to the Dinka, Kalenjin and Nuer languages. Except for some elders living in rural areas, most Maasai people speak the official languages of Kenya and Tanzania, Swahili and English. The Maasai population has been reported as numbering 1,189,522 in Kenya in the 2019 census, compared to 377,089 in the 1989 census, though many Maasai view the census as government meddling and therefore either refuse to participate or actively provide false information. Many Maasai tribes throughout Tanzania and Kenya welcome visitors to their villages to experience their culture, traditions, and lifestyle, in return for a fee.

The Maasai inhabit the African Great Lakes region and arrived via South Sudan. Most Nilotic speakers in the area, including the Maasai, the Turkana and the Kalenjin, are pastoralists and are famous for their fearsome reputations as warriors and cattle rustlers. The Maasai and other groups in East Africa have adopted customs and practices from neighboring Cushitic-speaking groups, including the age-set system of social organization, circumcision, and vocabulary terms.