Purpose Prevention of mental disorders is a rapidly growing area of research with substantial potential benefits for population health. This paper reviews the evidence base for prevention of depression, anxiety, and schizophrenia. Methods We synthesized evidence from recent systematic reviews and meta-analyses published between 2013 and 2018 on prevention of depression, anxiety, and first-episode psychosis. We included reviews of randomized controlled trials testing psychological, psychosocial, and pharmacological preventive interventions. Results There is good evidence that depression and anxiety can be prevented, although effect sizes are generally small. Indicated prevention of first-episode psychosis appears promising. Economic evaluations provide support for prevention of depression, anxiety, and first-episode psychosis, but more studies evaluating costs and benefits are needed to strengthen the knowledge base, particularly regarding long-term outcomes, which include chronicity of the prevented disorder, as well as later occurence of important comorbid mental and physical health problems. Promising areas for further development include internet- or computer-based prevention strategies, mindfulness-based interventions, and integration of prevention programs within occupational settings. Conclusions A number of interventions to prevent mental disorders are efficacious. While intervention effect sizes are generally small for prevention of depression and anxiety, they may nonetheless be of significant population benefit. Using the growing evidence base to inform policy and dissemination of evidence-based prevention programs is critical for moving prevention science into real-world settings.