Criteria air pollutant exposure has always been a major factor that negatively impacts human health through different pathways. One of the critical concerns is adverse birth outcomes associated with criteria air pollutant exposure such as low birth weight, preterm births, neonatal mortality, etc. Recent studies show that criteria air pollutant exposures are strongly associated with the elevated risk of preterm births defined as any birth occurring before 37 weeks of gestation. Bangladesh is one of the most polluted and has the highest preterm birth rate compared to other countries of the world. Although numerous global and regional studies investigate the impacts of criteria air pollutant exposure on preterm births, limited studies are available that investigated the impacts of the major criteria air pollutants on preterm births in recent years for Bangladesh. In this study, we employ the criteria air pollution data from the MERRA-2 model and satellite-sensed data regionally scaled for Bangladesh from NASA Giovanni (version 4.38) coupled with exposure-response modeling to quantify the impacts of CO, O₃, PM_2.5, SO₂, and NO₂ exposure on preterm births in Bangladesh during the 2015-2019 period. Based on the air quality analysis, the highest CO, O₃, PM_2.5, SO₂, and NO₂ exposures were observed in 2018 up to 272.8 /m³, 88.2 ppbv, 62.9 /m³, 20.5 /m³, and 11.6 ppbv respectively. This elevated amount of criteria air pollutant exposure has had direct implications for the increased rate of preterm births in Bangladesh. During 2015-2019, CO, O₃, PM_2.5, SO₂, and NO₂ exposures from all natural and anthropogenic emissions combinedly caused from 0.18 million [95% confidence interval (95CI): 0.08 – 0.29 million] up to 0.20 million [95CI: 0.08 – 0.32 million] preterm births among 4.3 million annual total live births each year which indicated a 4.4-4.9% preterm birth rate exclusively attributable to criteria air pollutant exposure in Bangladesh. Our study is critical for the overall wellbeing of the under-represented women and children in Bangladesh as it facilitates the quantitative evidence of preterm births caused by major air pollutant exposure and advocates the reduction of countrywide air pollution and establishment of well-aware community by facilitating low-cost air quality monitoring system in each household, necessary reformation of pollution prevention policies & regulations in national level and strict as well as vigilant law enforcement on human activities that causes air pollution.