We investigate how user-managed small-scale irrigation can influence inclusive rural transformation. Cultivating inclusive rural transformation is key to sustainable growth and poverty reduction in developing countries, but existing research rarely analyses the holistic impacts of rural development projects on this process. We use a combination of quantitative and qualitative data to rigorously measure impacts and uncover the causal pathways of a canal irrigation project for rice farmers in the Philippines, finding that positive impacts were heavily determined by market access and the strength of the local economy. We also find limited impacts for poorer farmers located further downstream on the irrigation canals. Based on these findings, we draw several lessons about the complementary conditions and support that are required in order for irrigation to be an effective tool in promoting inclusive rural transformation in developing countries.