The purpose of this literature review is to systematically examine policy and practice intervention research and assess the impact of those interventions on high school dropout and school completion rates. This systematic review extends the literature by (a) describing both policy and practice interventions, (b) synthesizing findings from experimental or quasi-experimental research, and (c) examining the common elements of effective interventions. Specifically, this review addresses two main questions. First, what are the characteristics of the empirical literature examining high school dropout or school completion interventions? Second, what are the common elements of effective policy or practice interventions for reducing high school dropout rates or increasing school completion rates? Findings indicate that despite research highlighting the need to address multiple risk factors and the need for early intervention, the bulk of current empirical research is focused on single-component, individual, or small group interventions delivered at the high school level. Further research is needed to provide guidance to schools regarding the integration of dropout efforts with other school initiatives. Multitiered frameworks of support are suggested as a structure for accomplishing this effectively and efficiently.