Irrigation development is crucial to ensure food security and reduce climate vulnerability in Sahelian countries. However, 'irrigation' covers a wide variety of systems and practices, some of which are little known to policymakers and scientists. In this paper, we discuss various technical and managerial options, including free or controlled flooding, improved inland valley, flood recession cropping, and full water control in small- and large-scale irrigation schemes. Over the last few decades, planners promoted two contrasting strategies. One is based on large schemes, commercial or public, where yields have been improved but water is still over-used. The other strategy is based on small private irrigation which is expanding fast throughout West Africa. It is necessary to better understand the various systems used by farmers throughout the Sahel region to select the less costly and most relevant strategies for irrigation development.