The aim of this study was to examine the gender differential effects of eating habits and physical activity on overweight and obesity among school-aged adolescents in Bangladesh. Nationally representative data extracted from the 2014 Global School-based Student Health Survey (GSHS) were utilized. The survey collected information related to physical and mental health from 2989 school-aged adolescents in Bangladesh. An exploratory data analysis and multivariate logistic regression model were employed in this study. Female adolescents were at a lower risk of being overweight or obese (AOR=0.573) than males, with a prevalence of 7.4% (males: 9.9%). The results showed that high consumption of vegetables (both: AOR=0.454; males: AOR=0.504; females: AOR=0.432), high soft drink consumption (both: AOR=2.357; males: AOR=2.929; females: AOR=1.677), high fast food consumption (both: AOR=2.777; males: AOR=6.064; females: AOR=1.695), sleep disturbance (both: AOR=0.675; males: AOR=0.590; females: AOR=0.555) and regular walking or cycling to school (both: AOR=0.472; males: AOR=0.430; females: AOR=0.557) were vital influencing factors for being overweight or obese among adolescents for both sexes. Sedentary activities during leisure time were also identified as significant predictors of being overweight or obese for males. Regular fruit and vegetable consumption, the avoidance of soft drinks and fast food, an increase in vigorous physical activity, regular attendance at physical education classes and fewer sedentary leisure time activities could all help reduce the risk of being overweight or obese for both sexes.