Obesity became recognized in the classification of diseases 79 years ago (1948-2017). Since then, it has risen exponentially to become a global treat to health affecting different populations. The estimation of obesity prevalence cannot be overstressed. Therefore, this study investigated the prevalence of overweight and obesity among secondary school students in Ilorin Metropolis, Nigeria. A cross-sectional design was adopted for this study; the population for this study comprised all the secondary school students in the metropolis. Multistage sampling method comprising stratified; proportionate and simple random was used to select 1,569 participants for this study. Four research questions and hypotheses were answered and tested for this study. Frequency counts and percentage was used to answer the questions and independent sample t-test was used to test the hypotheses at 0.05 significance level. Anthropometric measures of Body Mass Index. (BMI) and Waist-Hip Ratio (WHR) conducted for classifications into overweight and obesity using percentile ranking. The standardized instruments for data collection were weight scale (BF9015B model) and inelastic tape rule that provides 100g tension. All the measurements for this study were ISAK compliant. The four hypotheses were rejected and the percentage analysis of the data indicated that; 28.1% of the male students in the private schools were obese, 20.1% were obese in the public schools. In the female category, 23.0% were obese in the private schools while 21.8% were obese in the Public schools. The mean WHR for female in the private and public schools were 0.87 and 0.80 respectively. It was concluded that; overweight and obesity was prevalent in the schools but higher prevalent was recorded in the private schools. Regular participation in physical activity and routine assessment of overweight and obesity status of the students using BMI and WHR methods for monitoring and timely interventions were part of the recommendations.