Neretva is a river in Bosnia and Herzegovina and Croatia. The total length is 225 km, of which 203 km are in Herzegovina, while the final 22 km are in the Dubrovnik-Neretva county of Croatia.

The upper stream of Neretva has water of Class A purity and is almost certainly the coldest river water in the world, often as low as 7-8 degrees Celsius in the summer months. Neretva also has some endemic and very delicate, fragile life forms that are near extinction.

Neretva originates deep in the Dinaric Alps and flows through them creating a large gorge. It eventually expands into a wide valley which provides valuable agricultural land. There exists a large accumulation lake near Jablanica, created on the Neretva and at least three hydroelectric dams between Jablanica and Mostar.

The Bosnian government has recently made serious plans to allow foreign investors to build several more dams in upper stream and destroy the canyon by flooding it. This is protested by environmentalists who wish for the canyon, considered at least as beautiful as the Tara canyon in the nearby Montenegro, to remain untouched as it has been so far. The smaller rivers of Rakitnica, Rama and Trebižat flow into Neretva from the right, while Buna and Bregava flow into it from the left. The last 30 km of Neretva's stream form an alluvial delta, before the river empties into the Adriatic Sea. The biggest city on the Neretva is Mostar. Other towns on the Neretva include Konjic, Metković, Jablanica, Čapljina as well as the historical village of Počitelj.

The Old Bridge (also Stari most), a major architectural monument over Neretva in Mostar and a World Heritage Site, was destroyed by Croatian shelling during the war in Bosnia and Herzegovina on November 9 1993. The bridge was rebuilt and the grand opening was held on July 23, 2004.