Afghanistan's ethnically and linguistically mixed population reflects its location astride historic trade and invasion routes leading from Central Asia into South and Southwest Asia. Pashtuns are the dominant ethnic group, accounting for about 38% of the population. Tajik (25%), Hazara (19%), Uzbek (6%), Aimaq, Turkmen, Baluch, and other small groups also are represented. Dari (Afghan Persian) and Pashto are official languages. Dari is spoken by more than one-third of the population as a first language and serves as a lingua franca for most Afghans, though the Taliban use Pashto. Tajik, Uzbek, and Turkmen are spoken widely in the north. Smaller groups throughout the country also speak more than 70 other languages and numerous dialects.

Afghanistan is an Islamic country. An estimated 84% of the population is Sunni, following the Hanafi school of jurisprudence; the remainder is predominantly Shi'a, mainly Hazara. Despite attempts during the years of communist rule to secularize Afghan society, Islamic practices pervade all aspects of life. In fact, Islam served as the principal basis for expressing opposition to the communists and the Soviet invasion. Likewise, Islamic religious tradition and codes, together with traditional practices, provide the principal means of controlling personal conduct and settling legal disputes. Excluding urban populations in the principal cities, most Afghans are divided into tribal and other kinship-based groups, which follow traditional customs and religious practices.