In the past 10 years, mental and behavioral health has seen a proliferation of technology-based interventions in the form of online and other computer-delivered programs. This paper focuses on technology-based treatment and preventive interventions aimed at benefitting children and adolescents via either involving the parents and families, or only the youth. The review considered only technology-based interventions that had at least one published study with a randomized controlled trial design. Questions being addressed included: (1) What are the technology-based interventions in the mental/behavioral health area that have been systematically evaluated in published studies? (2) What are the common and unique characteristics of these interventions and their application with respect to sample characteristics, target problems, and technology characteristics (platforms, structures, elements, and communication formats)? and (3) Which intervention approaches and strategies have accrued the greatest evidence? The review identified 30 technology-based psychosocial interventions for children and families, 19 of which were parent or family-focused (32 studies) and 11 of which were youth-focused (in 13 studies). For the parent/family-focused interventions, greatest promise was found in those that addressed either youth behavioral problems or depressive/anxious symptoms, as well as more general bolstering of parenting efficacy. The youth-focused interventions showed some promise in reducing depressive/anxious symptoms. Advantages and disadvantages of the technology-based approaches were considered, and areas for future research and development were discussed.