Objective: To identify major dietary patterns and their association with socioeconomic status (SES) and food insecurity in two major ethnic groups living in Urmia, north-west Iran. Design: A cross-sectional study. Setting: All four geographical zones of Urmia city. Subjects: Participants (n 723; 427 women and 296 men), aged 20-64 years, from two ethnic groups (445 Azeri Turks and 278 Kurds). Results: Three major dietary patterns were extracted: 'Traditional High SES' (THS), 'Traditional Low SES' (TLS) and 'Transitional'. After adjusting for confounders, the THS pattern was positively associated with education level and negatively associated with moderate or severe food insecurity in Azeri Turks; whereas, among Kurds, it was more common in women and positively associated with age. The TLS pattern was more common among men and negatively associated with educational level and all levels of food insecurity in Azeris; while, among Kurds, it was more common among men, positively associated with being married and negatively associated with household income/capita. The 'Transitional' pattern was positively associated with being employed and negatively associated with age and all levels of food insecurity in Azeris; while, among Kurds, it was more common among men and negatively associated with age, being married and physical activity level. Conclusions: Findings suggest that household SES and food insecurity are associated with detrimental dietary patterns and that this effect may be stronger than cultural and ethnic background. These patterns differ by age and gender. Therefore, such characteristics should be considered in planning and formulating diet-related policies and programmes.