<p>Non-governmental organizations (NGOs) have emerged as significant stakeholders in global governance, yet limited research has been conducted on their performance and efficiency. This study aims to fill this gap by examining the internal and external factors that drive NGO efficiency, using the cognitive evaluation theory (CET) as a conceptual framework. Through a systematic literature review of 57 papers published in peer-reviewed journals between 2002 and 2025, this research identifies key motivations for enhancing NGO efficiency, including intrinsic factors such as professionalism and extrinsic factors such as performance feedback. The findings highlight the importance of both internal and external motivators in improving NGO efficiency. Furthermore, this study proposes a research agenda to guide future investigations in this field. By providing a comprehensive review of existing literature and introducing the CET framework to the context of NGOs, this study contributes to the understanding of NGO efficiency and offers valuable insights for further research in this area. It is suggested that both performance feedback (extrinsic motivation) and NGO professionalism (intrinsic motivation) positively impact NGO performance. NGOs need to utilize performance feedback effectively, while policymakers and government agencies should foster a conducive feedback environment and regulations that motivate NGOs to evolve into learning organizations.</p>