There are several methods of assessing overweight and obesity. Several studies conducted in different populations indicate that neck circumference (NC) can be used as a simple measure of overweight and obesity. This study was conducted to evaluate NC as a marker of overweight and obesity and to determine respective cutoff values for Bangladeshi male and female participants. This cross-sectional observational study was conducted with during July 2013-June 2014 among randomly selected 871 Bangladeshi participants (male = 496 56.9%, female = 375 43.1%, aged >18 years) who visited Outpatient Department of United Hospital, Bangladesh Institute of Research and Rehabilitation in Diabetes, Endocrine and Metabolic disorders, primary health-care centers located in Dhaka, Savar, Gazipur. NC of participants was taken in centimeter to the nearest 1 mm, using plastic tape measure. Main outcome included NC, waist circumferences (WC), body mass index (BMI), and waist: hip ratio (WHR). Pearson's correlation coefficients indicated a significant association between NC and height (men, = 0.33; women, = 0.28; < 0.0001), weight (men, = 0.61; women, = 0.55; < 0.0001), BMI (men, = 0.51; women, = 0.41; < 0.0001), WC (men, = 0.61; women, = 0.46; < 0.0001), hip circumference (men, = 0.61; women, = 0.44; < 0.0001), WHR (men, = 0.22; women, = 0.18; < 0.0001). Receiver operating characteristic curve analysis showed that NC ≥34.75 cm in men (area under curve AUC: 0.77; < 0.001) and ≥31.75 cm in women (AUC: 0.62; < 0.001) were the best cutoff value for BMI ≥23 (overweight). NC ≥35.25 cm in men (AUC: 0.82; < 0.001) and NC ≥34.25 cm in women (AUC: 0.76; < 0.001) were the best cutoff value for BMI ≥27.5 (obesity). NC ≥35.25 cm in male (AUC: 0.83; < 0.001) and NC ≥31.25 cm in women (AUC: 0.65; < 0.001) were the best cutoff value for WC >90 cm in men and > 80 cm in women, respectively. NC ≥34.45 cm in male (AUC: 0.59; = 0.001) and NC ≥31.25 cm in women (AUC: 0.66; = 0.008) were the best cutoff value for WHR >0.9 in men and >0.8 in women, respectively. NC measurement is a simple, convenient, inexpensive screening measure to identify overweight and obese participants. Men with NC ≥34.75 cm and women with NC ≥31.75 cm are to be considered overweight while men with NC ≥35.25 cm and women with NC ≥34.25 cm are to be considered obese. NC ≥35.25 cm in male and NC ≥31.25 cm in women were the best cutoff value for abdominal obesity.