The Beneden Merwede (Dutch pronunciation: [bəˌneːdəˈmɛrʋeːdə], Lower Merwede) is a stretch of river in the Netherlands, mainly fed by the river Rhine. It starts as the continuation of the Boven Merwede after the branching-off of the Nieuwe Merwede ship canal. It flows from Hardinxveld-Giessendam to Dordrecht, where it splits into the Noord and Oude Maas rivers. Its length is 14.8 km.^[1] The river is part of the main shipping route between the port of Rotterdam and the industrial region of the Ruhr, Germany.

There is a road bridge and, more to the east, a railroad bridge between the railway stations Dordrecht Stadspolders and Hardinxveld-Giessendam on the line Dordrecht-Gorinchem.