The Durrani are one of the two major tribes of the Pashtun people, the other being the Ghalzai, and derive descent from the first Afghan king, Ahmad Shah Durrani. He was named king in 1747, by agreement of a loya jirga and the Muslim ulama of Afghanistan. There are also Durranis in Pakistan.
The Durranis are dominated by two main clans, the Zirak and the Panjpia. The Zirak have historically been the elite, and the Afghan royal family came from the Mohamedzai subclan of the Ziraks. Afghan President Hamid Karzai is from the Popalzai subclan of the Ziraks. The Panjpia subclans include the Alizaj, Izhak, Koginaj, Maku, and Nurzai.
In the 19th century, the Durranis lost the land east of the Indus River, but a Durrani clan ruled Afghanistan until 1973. They were in constant conflict both among internal clans, and with the other main tribe, the Ghilzai. 
Resistance to the Soviets, in the Afghanistan War (1978-1992), began with Durranis in the Kandahar area. While there was no single organization, important factions included the Harakat-e-Iquilab Islami (Movement of the Islamic Revolution) led by Maulvi Mohammed Nabi Mohammed and Hizb-e-Islami (Islamic Party of Afghanistan), initially led by Maulvi Younis Khalis. The latter was later to split into two factions, one under Gulbuddin Hekmatyar.
Hamid Karzai, the current president of Afghanistan, is a Durrani.