<p>This study examines the determinants of polygynous marriage in districts across India, utilising cross-sectional data from the fifth round of the National Family Health Survey (NFHS-5), conducted between 2019 and 2021. A binary and multilevel logistic regression model was employed to identify predictors of polygyny. While the findings indicate a decline in the prevalence of polygynous marriages over time, the practice remains significantly prevalent in certain regions, particularly in Mizoram, Sikkim, and Arunachal Pradesh. The analysis reveals that the prevalence of polygyny is higher among women age-group 25–34 and 35–49, those with no formal education or only primary-level education, and those engaged in consanguineous marriages. Furthermore, women belonging to the Muslim religion, Scheduled tribes, and the poorest wealth quintiles, as well as those residing in rural areas, are disproportionately affected. Individual- and community-level factors were identified as significant predictors of polygyny. Despite being prohibited under the Indian Penal Code—with exceptions for Muslim communities—polygyny persists across various regions of India. The findings underscore the need for targeted interventions to address this issue, particularly through enhancing educational access and raising awareness within marginalised and vulnerable communities.</p>