Cầu River (Vietnamese: Sông Cầu) is a river of northern Vietnam. It flows through the provinces/cities of Bắc Kạn, Thái Nguyên, Bắc Giang, Hanoi, Bắc Ninh. It begins at the Phia Bioóc Peak in Chợ Đồn District, west of mountainous province of Bắc Kạn.
The river has a length of 288 km and basin area of 6,030 km².