The Organisation pour la mise en valeur du fleuve Sénégal (OMVS; in English Senegal River Basin Development Authority) is an organisation grouping Guinea, Mali, Mauritania and Senegal for the purpose of jointly managing the Senegal River and its drainage basin. It was founded in 1972.
A predecessor organisation, the Organisation des Etats Riverians du Fleuve Sénégal (or Senegal River Riparian States Organisation), with the four border countries—Guinea, Mali, Mauritania, and Senegal—was established to manage the Sénégal River drainage basin and the river itself. This organisation dissolved when Guinea withdrew due to political tensions, and the three remaining countries subsequently created the OMVS. Guinea returned to the organisation in 2005.