According to the World Health Organization and Inter-Agency Standing Committee, mental health needs arising from a humanitarian disaster are best addressed by accessing the existing mental health services, and by capacity building initiatives that improve and extend these, rather than by setting up separate services for disaster survivors. Capacity building of primary health care (PHC) workers on mental health issues is an important part of a humanitarian assistance, but also an essential prerequisite for closing the treatment gap for mental disorders in low and middle-income (LAMI) countries. Effectiveness of interventions to change health professionals’ behavior and practices should be a priority area for researchers in developing countries. Still, there is a limited evidence on effectiveness of mental health training for PHC workers in emergency and post-emergency settings in LAMI countries.