The Kafir harp (known in the local language as waj, waji, vaj or vaji) is a traditional four- or five-stringed arched harp used by the Nuristanis native to the Nuristan Province of northeastern Afghanistan and Lower Chitral District of northwestern Pakistan. It is played during social gatherings, and to accompany epic storytelling or songs of heroic tales.

Similar harps used to be widespread in ancient times throughout Central Asia and India, and this harp possibly entered Afghanistan during the spread of Buddhism across the region but today the waji is not used in any other part of Afghanistan. It has been compared to the ennanga of Uganda and harp designs used in Sumer and ancient Egypt as far back as 3000 BC.