Schools can play an important role in addressing growing concerns about adolescent mental health. Mental health of high school students has predominantly been the focus in literature with less emphasis on younger adolescents. This review identified articles published in the last decade that described evaluations of middle school-based mental health interventions and randomized participants to an intervention or control condition. Fourteen interventions met the inclusion criteria. About two-thirds of interventions were based on mindfulness or cognitive behavioral therapy. Many trials utilized racially diverse, low-income samples. All interventions were delivered to groups, and three contained a parent component. Five trials increased rigor by using an active control condition. Almost two-thirds of the interventions were effective (p < 0.10) in reducing at least one depression, anxiety, affect, or internalizing symptom outcome compared to a control group. This article provides information about intervention characteristics, efficacy, theoretical framework, and acceptability/feasibility.