Glob Ment Health (Camb). 2015; 2: e12. Published online 2015 Jul 14. doi: 10.1017/gmh.2015.10 Low and middle income countries (LMICs) are facing an increase of the impact of mental health problems while confronted with limited resources and limited access to mental health care, known as the ‘mental health gap’. One strategy to reduce the mental health gap would be to utilize the internet to provide more widely-distributed and low cost mental health care. We undertook this systematic review to investigate the effectiveness and efficacy of online interventions in LMICs.