Book excerpt: This paper analyzes the contributions of a non-goverment organization in improving management of small-scale irrigation systems in Sri Lanka. It documents the decision-making processes in the non-government organization and the context in which this decision making takes place: government policies and policies of non-government organizations in improving the performance of small scale irrigation systems and in assisting the rural population in general. The site selected for research was the Tank Settlement Project in Hamhantota District, Southern Sri Lanka.