Islam in Afghanistan began to be practiced after the Arab Islamic conquest of Afghanistan from the 7th to the 10th centuries, with the last holdouts to conversion submitting in the late 19th century.

Islam is the official state religion of Afghanistan, with approximately 99.7% of the Afghan population being Muslim. Roughly 85% practice Sunni Islam, belonging to the Hanafi school of Islamic law, while around 15% are believed to be Shias. Most Shiites belong to the Twelver branch and only a smaller number follow Ismailism.