Islam is the official state religion of Afghanistan, with approximately 99.7% of the Afghan population being Muslim.
About 80-89% practice Sunni Islam and belong to the Hanafi Islamic law school while 10-19% are Shi'a, majority of whom follow the Twelver branch with smaller numbers of Ismailis. Some influence of Sufism may exist among both Sunni and Shi'a communities.
For Afghans, Islam represents a potentially unifying symbolic system which offsets the divisiveness that frequently rises from the existence of a deep pride in tribal loyalties and an abounding sense of personal and family honor found in multitribal and multiethnic societies such as Afghanistan.
Islam is a central, pervasive influence throughout Afghan society; religious observances punctuate the rhythm of each day and season. In addition to a central Friday mosque for weekly communal prayers which are not obligatory but generally attended, smaller community-maintained mosques stand at the center of villages, as well as town and city neighborhoods. Mosques serve not only as places of worship, but for a multitude of functions, including shelter for guests, places to meet and gossip, the focus of social religious festivities and schools. Almost every Afghan has at one time during his youth studied at a mosque school; for many this is the only formal education they receive.
Because Islam is a total way of life and functions as a comprehensive code of social behavior regulating all human relationships, individual and family status depends on the proper observance of the society's value system based on concepts defined in Islam. These are characterized by honesty, frugality, generosity, virtuousness, piousness, fairness, truthfulness, tolerance and respect for others. To uphold family honor, elders also control the behavior of their children according to these same Islamic prescriptions. At times, even competitive relations between tribal or ethnic groups are expressed in terms claiming religious superiority. In short, Islam structures day-to-day interactions of all members of the community.
Afghanistan is home the Mosque of the Cloak of the Prophet Muhammad, in Kandahar, which is considered one of the holiest Islamic sites in the country.