In the quest to improve projects, project actors rely on sound project evaluation. However, project evaluation can be complex and challenging. This study aims to explore and define project evaluation and reveal how it can promote continuous improvements within and across projects and organizations. A review of extant literature finds four constitutive properties for project evaluation: criteria, times, evaluands, and evaluators. Based on the action design research of 75 projects in 21 organizations, the study finds three evaluation perspectives: process, outcome, and learning. Understanding the multidimensionality of project evaluation through the seven identified dimensions offers a meaningful conception of project evaluation.