Background Globally, across many regions, the prevalence of hypertension is higher among men aged ≥ 30 years, but for Bangladesh, a national survey depicts a contrast from the norm. In this paper, we examine the sex and age difference in hypertension among the Bangladeshi population and explore its associated factors.Methods Secondary analysis was conducted using data from the Bangladesh Demographic and Health Survey (BDHS) 2017–2018, a nationally representative survey that involved a two-stage stratified sample of 675 households in urban (250) and rural (425) enumeration areas. The analytical sample consisted of 12,476 individuals aged 18 or older (6,955 women and 5,521 men). We conducted univariate and bivariate tests to analyze hypertension variations across sex, age, and other factors. We used multivariable logistic regression models and logit-based marginal probabilities to investigate age and sex differences as well as their interactions in hypertension while estimating the marginal effects of sex for each age-group to assess the significance of sex differentials in hypertension across the life course.Results Our study revealed a noteworthy trend: Women have a 5-percentage point lower hypertension prevalence than men in their early twenties, but this reverses when women reach their early thirties, with a 5-percentage point higher prevalence compared to men. After adjusting for confounders and age-sex interaction in females, the odds of hypertension were significantly higher (AOR: 3.6, 95% CI: 1.9–6.6) in the 35–39 years age-group, potentially leading to a combined burden of chronic and reproductive morbidity.Conclusion With rising hypertension and stagnant maternal health in Bangladesh, women of reproductive age face higher risks of chronic and reproductive complications, impacting maternal mortality and morbidity and burdening the healthcare system. Recognizing common factors contributing to early hypertension in Bangladeshi women enables targeted interventions, model testing, and strategic adjustments to the national non-communicable disease management pathway.