National Highway 01 or NH01, formally called the Ring Road (Pashto: د افغانستان حلقوي سړک; Dari: شاهراه حلقوی افغانستان), is a 2,200-kilometre (1,400 mi) two-lane road network circulating inside Afghanistan, connecting the following major cities (clockwise): Kabul, Maidan Shar, Ghazni, Kandahar, Delaram, Herat, Maymana, Sheberghan, Mazar-i-Sharif, Puli Khumri and back to Kabul.

It has extensions that connect Jalalabad, Bamyan, Khost, Lashkargah, Zaranj (Route 606), Farah, Islam Qala, Torghundi, and Kunduz.

In the west, Iran participated in the two-lane road construction between Islam Qala and the western Afghan city of Herat.

Approximately 35 percent of Afghanistan's population lives within 50 km (31 mi) of the Kabul to Kandahar portion of the Ring Road.

The Kabul–Kandahar highway underwent major repairs, carried out by the United States and Japanese governments with planning and design by Turkish and Indian engineers.