The objective of the proposed systematic review is to summarize the available evidence on the effects of prevention and intervention programs aimed at primary and secondary students for increasing school completion or reducing school dropout. Program effects on the closely related outcomes of school attendance (absences, truancy) will also be examined. Moreover, when accompanying dropout or attendance outcomes, effects on student engagement, academic performance, and school conduct will be considered. The primary focus of the analysis will be the comparative effectiveness of different programs and program approaches in an effort to identify those that have the largest and most reliable effects on the respective school participation outcomes, especially with regard to differences associated with treatment modality, implementation quality, and program location or setting. In addition, evidence of differential effects for students with different characteristics will be explored, e.g., in relation to age or grade, gender, race/ethnicity, and risk factors. Because of large ethnic and socioeconomic differences in graduation rates, it will be particularly important to identify programs that may be more or less effective for disadvantaged students. The ultimate objective of this systematic review is to provide school administrators and policymakers with an integrative summary of research evidence that is useful for guiding programmatic efforts to reduce school dropout and increase school completion.