Purpose: Research on juvenile reoffending has experienced an ecological turn, marked by an impressive expansion of studies that test the relation between elements of residential context and reoffending. Yet, to date, little consensus exists regarding what ecological factors matter, how they affect reoffending, and for whom they matter most. To address this gap, this study takes stock of research that tests the relationship between ecological factors and reoffending among youth. Methods: A systematic review, in accordance with PRISMA-P guidelines, of quantitative studies (k = 27) was conducted. Evidence was synthesized quantitatively (i.e., meta-analytically, tabularly) and qualitatively (i.e., narratively). Results: A variety of ecological factors have been tested, but results are inconsistent and reflect relatively few contexts and samples. The most frequently tested factor, concentrated disadvantage (k = 15), is a predictor of re-arrest (pooled OR = 1.09, p = .01). Inconsistent findings regarding other factors seem to reflect sample and study characteristics. Conclusions: Research to date does not indicate summarily rejecting or accepting ecological factors as risk factors for reoffending. To further clarify the ecology-reoffending relationship and inform recidivism reduction interventions, future research should sample from unexamined contexts and test theoretically meaningful relationships via approaches that strengthen causal inference.