Objectives: This study was designed to determine the anthropometric characteristics and prevalence of obesity among secondary and undergraduate students in Sagamu. Methods: This cross-sectional study involved a selection of 260 students aged 10 to 33 years in Sagamu using a convenience sampling method. The weight, height, and waist and hip circumferences of each subject were measured. The body mass index was then calculated. Data were analyzed using SPSS version 25.0 and p-values< 0.05 were considered statistically significant. Results: The age ranges were 1o to 17 years (Secondary school (SS) students) and 14 to 33 years (undergraduate students). There were 130 students in each group, comprising 52.7% males and 47.4% females. Underweight was commoner among the SS students (20.8% versus 6.2%). Most of the subjects were of normal weight 52.3% in SS and 68.5% in undergraduates. Only 3.1% of SS students were obese compared to 4.6% of undergraduate students. The mean BMI of SS students (22.2± 0.39 versus 23.24±0.34) was statistically lower (p=0.019). The mean waist circumference of SS students (66.92±0.44 versus 74.64±0.67) was also statistically lower (p=0.000). The mean BMI of SS students was higher in females than in male subjects (23.14±0.62 versus 20.86±0.42). The mean waist and hip circumferences and BMI were lower in female subjects for both study groups. Conclusions: The mean BMI and hip circumferences were higher in female subjects while the mean waist circumferences were lower in females than males in both study groups.