This study compared consistency of age- and gender-specific self-reported height and weight and calculated body mass index among a sample of high school students in Taipei County, Taiwan to reference values for Taiwanese school-aged youth obtained through national studies. Taipei high school students provided self-reports of height and weight that were similar to national reference values. Use of self-reported height and weight in this sample appeared warranted and may reliably be used to calculate aggregate indices of body mass, overweight, and obesity. This study compared prevalence of overweight and obesity in the current sample with other adolescent populations using international criteria (International TaskForce on Obesity). Using these criteria, 17.6% of boys and 9.4% of girls met the definition of overweight and 3.7% of boys and 1.6% of girls met the definition of obesity. While use of self-reported height and weight appears justified in this sample, researchers should not assume self-report measures will always be accurate. Researchers considering use of self-reported height and weight should compare their results to normative reference values when possible to increase confidence in using self-report measures of height and weight.