The Supraśl is a river in east Poland in Podlaskie Voivodeship, a tributary of the Narew river (near Złotoria), with a length of 93,8 kilometres and the basin area of 1,844.4 km.

Supraśl is the source of the drinking water for Białystok.

Słoja (r), Sokołda (r), Kamionka (l), Płoska (l), Pilnica (l), Czarna (r), Biała (l)

• Michałowo
• Gródek
• Supraśl
• Wasilków