The River Stort is a river in Essex and Hertfordshire, England. It is 24 miles (38 km) long and flows from just south of the village of Langley to the River Lea at Hoddesdon.

Unusually, the town of Bishop's Stortford does not derive its name from the River Stort, but the other way around. The 16th-century cartographers Christopher Saxton and William Camden named it the Stort, assuming the town of Stortford was named for its ford. The river was originally called the Stour.

The Stort Navigation is the canalised section of the River Stort running 22 kilometres (14 mi) from Bishop's Stortford to its confluence with the Lee Navigation. It has 18 locks.