This article proposes a model of student school engagement, comprising aspirations, belonging, and productivity. From this model, items for the Student School Engagement Measure (SSEM) were developed. The SSEM was validated with data from 396 eighth graders in an urban school district. Utilizing structural equation modeling, the second-order empirical model of the SSEM was found to fit the data well, to have good reliability for the three factors, and to be predictive of district-identified risk factors and state standardized academic assessment results. These results suggest that the Student School Engagement Model and the SSEM may be useful tools for understanding which students might be at increased risk for school dropout and how to intervene to support school completion. Recommendations for practitioners and future research are given. (Contains 4 tables and 3 figures.)