Abstract: Background and Objective: There is paucity of data on the association between body weight and age or gender in Nigeria. This study investigated the body weight distribution amongst sexes and different age groups in educational institutions in Ota, Southwest Nigeria. Materials and Methods: The participants, 1394 (609♂; 785♀) healthy persons, were randomly selected from four schools in Canaanland, Ota and divided into six age groups: 2-5, 6-12, 13-19, 20-39, 40-59 and 60-75 years. Body weight was categorized into normal weight, underweight, overweight and obesity using CDC age and sex-specific BMI cut-offs for 2-19 years and WHO cut-offs for 20 years and above. Strength of association was assessed by correlation and regression analyses. Results: Underweight was prevalent at early childhood (22.7%) whereas obesity was predominant at middle adulthood (26.4%). Correlation was strong (p<0.001) between age and the anthropometric parameters: Weight (0.696); height (0.317); BMI (0.612) and body weight category (0.200). Gender had significant correlation with weight (-0.314, p<0.001) and height (-0.056, p<0.005). Body weight correlated more with age compared to gender. Conclusion: Age and gender had significant influence on the body weights of the studied population and could be factored into the national scheme for health and nutritional improvement.