The field of physical activity (PA) and its successful promotion in youth could have a significant impact on population health; however, 93% of Canadian youth are not meeting the recommended national PA guidelines for healthy growth and development (Colley et al., 2011). An identified limitation of existing reviews of the relevant research has been the prominent focus on reporting internal validity without systematically addressing issues related to the translatability of the research into health promotion practice (i.e., external validity) (Kriemler et al., 2011). This review used the RE-AIM (Reach, Effectiveness, Adoption, Implementation and Maintenance) framework to determine the extent to which intervention studies promoting PA in school-aged youth (aged 12 to 17 years) report on factors that inform generalizability across settings and populations. A systematic search for controlled interventions conducted within the last ten years identified 51 studies that met the selection criteria. Studies were coded independently by two members of the research team using the RE-AIM data extraction tool (Akers, Estabrooks, & Davy, 2010). Most of the studies (52.9%) were cluster randomized controlled trials. The average reporting across RE-AIM indicators varied by dimension (reach=73.1%; efficacy=77.1%; adoption=35.5%; implementation=54.2%; maintenance=12.4%). The majority of the studies focused solely on the efficacy of the intervention at the individual-level. Conversely, very few studies reported on factors that affect external validity, such as representativeness of participants and settings, cost of implementation, and program sustainability (i.e., maintenance). Due to this lack of information, it is difficult to determine whether or not reportedly successful interventions are feasible and sustainable in an uncontrolled, real-world setting. This review adds data to support recommendations (Van Sluijs, McMinn, & Griffin, 2007) that interventions promoting PA in youth should include assessment of adoption and implementation issues, include long-term follow-up measures on an individual- and organization-level, and carry out cost effectiveness analyses.