Objective <p>Obesity and poor sleep quality are rising concerns in health discussions today, especially among young adults. Young adults may be more vulnerable to weight gain due to academic pressures and lifestyle choices, making this research particularly relevant. The goal of this study is to examine how body mass index (BMI) relates to various aspects of sleep quality in young adults in Bangladesh. An online cross-sectional survey was conducted involving 445 participants aged 18 to 25, who were mostly students. The Pittsburgh Sleep Quality Index (PSQI) was used to assess sleep quality.</p> Results <p>More than half of our participants (56.4%) reported having poor sleep quality. Those with poor sleep had a higher average BMI of 24.11&#xa0;kg/m² compared to 22.36&#xa0;kg/m² for participants with good sleep. There was a notable inverse relationship between BMI and sleep duration, while correlations were positive with sleep latency, sleep disturbances, and the overall PSQI score. Individuals who were overweight and obese faced significantly greater odds of poor sleep quality. Additionally, being female and sleeping less than 6&#xa0;h a night were also significant predictors. This study reveals a troubling prevalence of poor sleep quality among young adults in Bangladesh and is associated with higher BMI, which has important implications for public health. Integrating sleep health promotion within obesity prevention initiatives could foster healthier futures for young adults.</p>