Background: Ready-to-eat (RTE) food consumption has become popular in the working community with the increase in full-time jobs and the limited time to prepare food. Although RTE food is essential for this community, its consumption causes obesity. In Myanmar, obesity is a modifiable risk factor for non-communicable diseases, causing increases in morbidity and mortality. This study aimed to identify the association between body mass index (BMI) and RTE food consumption among sedentary staff in Nay Pyi Taw Union Territory, Myanmar. Methods: A cross-sectional study was conducted in 2018, in which 400 respondents participated in face-to-face interviews. The study area was selected using simple random sampling and drawing method. Measuring tape and digital weighing scale were used to measure the height and weight of the respondents. BMI was calculated by dividing the weight by height squared (kg/m 2 ). Overweight and obesity were categorized by World Health Organization cut-off points. The collected data were analyzed using multiple logistic regression to estimate the adjusted odds ratio (AOR), and the 95% confidence interval (CI).Results: This study revealed that sedentary staff who consumed RTE food once or more per month were nearly five times more likely to be overweight and obese (AOR = 4.78, 95% CI 1.44-15.85) than those who consumed RTE food less frequently. In addition, five factors namely being older than 32 years (AOR = 3.97, 95% CI 1.82-8.69), preference for RTE food (AOR = 8.93, 95% CI 2.54-31.37), light-intensity of physical exercise (AOR = 3.55, 95% CI 1.63-7.73), sedentary leisure activities (AOR = 3.32, 95% CI 1.22-9.03), and smoking (AOR = 5.62, 95% CI 1.06-29.90) were positively associated with overweight and obesity. Conclusion: Frequent consumers of RTE food and less physically active sedentary staff were more likely to be overweight and obese. This study highlights the urgent need to raise awareness regarding healthy lifestyle behaviors among the working community to reduce the burden of obesity-related chronic diseases. Moreover, sedentary workers should be aware of the food-based dietary guidelines of the country. Policy makers should strictly enforce nutritional labeling of RTE food, and strictly prohibit over-branding of RTE food.