The aim of the current study was to correlate the effects of body weight, height, and body mass index (BMI) on thyroid volume of healthy undergraduate Saudi males by using ultrasound. After retaining an acceptance from the local ethics committee, a total of 100 (mean age was 21.8 ± 1.3 y; ages range from 18 to 22 y) participants were recruited between September 2016 and January 2018 in this prospective cohort study. Ultrasonographic measurements of the gland were performed using a HI vision Avius ultrasound unit (Hitachi), equipped with a high frequency direct contact 10 MHz linear array ultrasound probe. The calculated mean of thyroid volume was 7.5 ± 2.4 ml (right lobe volume was 3.9 ± 1.6 ml while that for left lobe was 3.6 ± 1.2 ml). Extremely statistically significant correlation (P<0.0001) was found between gland volume (ml) and participants' weight (kg), height (cm), and BMI (kg/m 2). In conclusion, the estimated thyroid volume was decreased significantly as participants' weight and BMI increase. In contrast, the volume increases significantly as height increases. Also, a local reference of thyroid volume among healthy undergraduate Saudi males was conducted.