The role of irrigation in gearing agriculture development towards a broader economic growth is undeniable. Accordingly, irrigation is growing into key operational strategy for governments and their agencies to increase agricultural productivity, thus combatting food insecurity and boosting overall growth. While agriculture absorbs rural workforce, generates income and increases food security, it has become the most important driver in freshwater exploitation. The rapid expansion of water demand leads to the generalized phenomena of imbalance between water supply and water demand. This increasing pressure on water resources urges enhancing water use efficiency. Water use efficiency has a significant role in addressing the challenges faced by the agricultural water use. While irrigation can increase yields of most crops by 100 to 400 percent, water resources remain limited. By 2030, irrigated land in developing countries will increase by 34 percent, while the amount of water used by agriculture will increase by only 14 percent. Increasing food production with less water, particularly in countries with scarce water resources, is one of the major challenges. Beyond the inevitable effect of water use efficiency on addressing these challenges, it is also effective to adapt to climate changing. Enhancing water use efficiency requires actions at all levels, from agricultural practitioners to scheme managers, and up to the policy-makers. The objective of this Guide Book is to show practical measures to improve water use efficiency in small-scale agriculture based on case studies from Burkina Faso, Morocco and Uganda. The Book not only presents applicable water use efficiency measures, but also guide the readers through their real-term implementation.