This manuscript describes results of a DFID and Wellcome Trust funded disaster mental health intervention in Bhaktapur district Nepal. The culturally-adapted intervention was tested in two earthquake affected communities (N = 240 persons), across three time points, using a matched cluster comparison design. Consistent with hypotheses, the intervention increased disaster preparedness, increased attributions to natural causes for the earthquake, reduced mental health symptoms (PTSD, depression), increased social cohesion, along with associated peer-based help-giving and help-seeking, and increased utilization of new forms of coping. Implications of the results are discussed, with emphasis on future research directions to determine the ‘active ingredients’ associated with treatment effects.