The socioeconomic factors have crucial effects on health inequality. The unequal distribution of socioeconomic factors may lead to the health inequality. This study aimed to determine and give priority to the socioeconomic factors affecting health in Iran in the experts’ point of view. This study was a sequential mixed methods research conducted in quantitative and qualitative phases. The study population consisted of 16 policymakers and experts in the field of economic and social determinants of health. The purposive stratified non-random sampling method was employed. The qualitative data were collected in a semi-structured interview and giving priority to factors was conducted using multiple criteria decision making with the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. The qualitative phase showed that the main socioeconomic factors determining health were the economic factors, income, education, sex, social class, and employment. The data analysis in TOPSIS technique showed that priority parameters were income, employment, and economic factors with coefficient of 0.66, 0.60, and 0.55, respectively. Paying attention to the socioeconomic factors may result in the increased equity and eventually the promoted public health. It is essential for policy makers to take this approach into account and improve the socioeconomic factors for attaining the promoted health outcomes.