This paper presents a systematic review of water sector interventions in achieving desired outcomes at various scales in developing countries. The synthesis is based on 40 studies assessing the impact of the six interventions included in the review. These cover four domains: built infrastructure, nature-based options, institutional interventions and financial/market mechanisms. The outcome area is adaptive capacity. Our meta-analysis suggests water-efficient irrigation systems and ecosystem-based management interventions stand out as particularly valuable tools for enhancing adaptive capacity, warranting specific attention. The scarcity of studies, particularly on coastal interventions, along with the fragmented nature of intervention types, highlights the extreme importance of combining evidence gap maps with meta-analyses of saturated intervention/outcome combinations.