This article provides an in-depth analysis of the program evaluation ecosystem within the European Union (EU), focusing on the methodologies, practices, and the lessons learned from various evaluation processes, especially those regarding the 2014–2020 programming period. It aims to offer a comprehensive understanding of how evaluation practices within the EU contribute to policy development, program effectiveness, and overall sustainable growth. The discussion extends to the lessons learned from past and ongoing evaluations. This includes insights into the challenges faced, such as aligning diverse program objectives with overarching EU policies, managing multi-level coordination, ensuring data quality, and addressing the dynamic nature of program environments. The present study also aims to provide a thorough understanding of the evaluation ecosystem in the EU, offering insights into its complexities, the sophistication of its methodologies and its significant role in steering the EU towards effective policy-making and sustainable growth. Through this analysis, the article contributes to the broader conversation on the importance and impact of program evaluation in the context of EU governance and policy implementation.