The explosion of programs aimed at improving adolescent girls' health in the developing world in recent years has almost certainly been beneficial, but do we really know how girls are faring in the wake of these various interventions? Good intentions are needed, but they do not always result in improved outcomes. The time is right to assess the impact of girl-focused programs. Through a structured, in-depth literature review, the authors of this paper on low and middle-income countries shed light on what we have learned and what we still need to learn.