Abstract Introduction The Asian earthquake and subsequent tsunami of December 2004, one of the largest natural disasters in history, resulted in the deaths of over 250,000 people and massive destruction in eight countries. The mental health consequences of the disaster remain relatively poorly explored. This study sought to go beyond the dose‐response paradigm to examine the effect of pre‐disaster socio‐cultural variables on common mental disorders (CMD) after the tsunami. Methods A cross‐sectional survey was conducted 9–11 months after the 2004 tsunami in a low‐income setting in South India to assess the association between CMD, disaster‐related losses and pre‐disaster socio‐cultural variables in a convenience adult sample of tsunami survivors. Results Sixty‐four percent (339) of the 532 individuals sampled and included in the analysis screened positive for CMD. Multivariate analysis showed that female gender, older age, poor quality marital life before the disaster and death of a primary family member due to the tsunami were associated with CMD. Discussion A large majority of the sample in an area of South India screened positive for CMD 9–11 months after the tsunami. These data served as an impetus in planning a long‐term, five‐year post‐disaster intervention. Accurate longitudinal data about risk and protective factors after a disaster are needed to plan medium‐ and long‐term interventions.