Introduction: Overweight and obesity (OW/OB) among adults is a public health concern in Indonesia. While OW/OB is generally attributed to consumption in excess of expended energy, understanding the perceptions of the causes of obesity among OW/OB individuals may provide insights for developing appropriate obesity-reduction interventions. Methods: This study used a mixed methods approach, comprising a quantitative online survey and in-depth interviews. The online “International Families and Food Survey” was conducted in 2014 by Global Market Insite (GMI) to elicit response of Indonesian women to 12 likely causes of obesity, based on a 5-point rating ranging from ‘definitely disagree’ to ‘definitely agree’. A total of 377 respondents aged 18-49 years from Jakarta participated, comprising 221 normal weight (NW) and 156 OW/OB based on World Health Organization (WHO) cut-offs. Additional 16 informants who fulfilled the inclusion criteria were recruited for indepth interviews to gather further insights on causes of obesity. Logistic regression was conducted to assess the likelihood of socioeconomic factors in predicting “agreement on the likely causes of obesity”. Results: The online survey showed that the NW and OW/OB respondents provided quite similar rating response to each of the likely causes of obesity. Unmarried and middle socioeconomic status (SES) respondents were significantly more likely to agree on the perceived causes of obesity, compared to married and high SES. In-depth interviews revealed OW/OB informants attributed obesity to environmental factors, compared to individual factors attributed by NW informants. Conclusion: Use of mixed methods approach provided insights for the development of obesity-reduction interventions among Indonesian adult women.