Overweight and obesity are currently an epidemic affecting both developed and developing countries. Sub-Saharan Africa has a double burden of being underweight and obese and has recently been battling an alarming increase in the prevalence of overweight. This study investigates the predictors of overnutrition among married women of reproductive age in Nigeria using the socioecological model (SEM) as a framework, and hypothesized that the Southern region will have higher burden of overnutrition compared to the Northern region.The cross-sectionalstudy design was adopted using the 2018 Nigeria Demographic and Health Survey. A total of 8531 non-pregnant married women met the inclusion criteria. Bivariate logistic regression and hierarchical multilevel logistic regression models were fitted, which were informed by the socioecological model framework.The prevalence of overnutrition was 31%. When all covariates were fitted in a model, being older, being a Christian, having tertiary education, having an older partner with tertiary education, being wealthy, and living in a rural area were predictors of overnutrition at multivariate analysis. The predictive power increases as one moves from a lower to a higher level in the SEM - 24.9%, 25.5%, and 25.7% at the individual, interpersonal, and community/societal levels, respectively. Theprevalence of overnutrition among Nigerian married women is high, especially in the Southern region. Predictors of overweight are at all the SEM levels; however, it is better to consider all the levels when planning public health interventions.