Background: E-mental health is a growing research field and an increasing number of computerized cognitive behavior therapy (cCBT) interventions are available for numerous mental health issues. Such interventions are often claimed to have added benefits, or collateral outcomes, when compared with traditional delivery platforms. Our aim was to systematically review the evidence of the cost-effectiveness, geographic flexibility, time flexibility, waiting time for treatment, stigma, therapist time, effects on help-seeking and treatment satisfaction of cCBT interventions for mental health. Method: The electronic databases Medline and Web of Science were searched for peer-reviewed controlled trials investigating collateral outcomes in computerized and internet-based CBT. Results: The literature search identified 101 published papers (95 studies), which were included in this review. The results suggest that cCBT interventions are cost-effective and often cheaper than usual care. Limited evidence was found with regard to geographic flexibility, time flexibility, waiting time for treatment, stigma and the effects on help-seeking. Personal support in cCBT was found to take many forms, was not limited only to therapists, and seemed to increase treatment adherence and reduce attrition. Treatment satisfaction with cCBT was found to be high, but more research on attrition due to dissatisfaction is required. Conclusions: Although the results of this systematic review on the collateral outcomes provide support for the potential of cCBT, these outcomes need to be better assessed within individual e-mental health studies.