This chapter presents an overview of different types of intervention studies, where participants can be either individuals, groups, or entire communities. Intervention studies include randomized controlled trials (RCTs), crossover trials, field trials, community trials, cluster RCTs (cRCTs), and non-randomized study designs. Different study designs have unique advantages and disadvantages, but the ultimate goal of any intervention study in the field of suicide research is to determine effective interventions for reducing suicidal behaviors. Important aspects of planning, implementing, and evaluating suicide preventive interventions (with an emphasis on a public health approach) are described and analyzed. Theoretical and methodological reflections are illustrated with practical examples of intervention studies in the field of suicide research (SUPRE-MISS, EAAD and OSPI-Eu-rope, SEYLE).