The Cam River (Vietnamese: Sông Cấm) is a river in northern Vietnam. It is one of the shorter distributaries of the Thai Binh River but geographically important as Hai Phong, Vietnam's second largest port is located on the banks of this river.
The start of the Cam River is the confluence of the Kinh Mon River and a smaller stream, the Hàn, in Hai Duong Province. From there it flows southeasterly, turning more easterly at Hai Phong before entering the Gulf of Tonkin as a wide estuary 5 kilometres (3.1 mi) farther downstream.
The entire length of the river is 7 kilometres (4.3 mi).