The current economic and political crisis has brought about a change in the environment in which Non-Governmental Development Organizations (NGDOs) have traditionally operated. This change can be summed up as a reduction in the funds received accompanied by an increase in the population they must serve. It is thus important to possess mechanisms that allow an analysis of the excellent work performed by NGDOs. A knowledge of the NGDOs’ efficiency in managing previous projects can contribute to improving their future achievements. This research aims to establish some objective indicators that permit an evaluation of the efficiency of these organizations. Firstly, a detailed analysis of the Spanish Agency for International Development Cooperation (AECID) regulation is conducted. This allows us to synthesise the indicators of a good performance by an NGDO based on a study of the eligibility criteria of public donors. The study concludes that the internal good practices criteria of the NGDOs of the AECID can be grouped into four criteria: experience, transparency and internal operations, human resources, and financial resources. Subsequently, a global performance measure of the NGDOs is built using a multi-criteria decision-making approach that minimises the distance from an ideal point whilst maximising the distance from an anti-ideal point. Our approach has been applied in the evaluation of 20 Spanish NGDOs.