OBJECTIVE: To verify whether neck circumference can predict cardiovascular risk factors and excess body fat in adolescents. METHODS: This cross-sectional study included male and female adolescents aged 10 to 14 years from Viçosa, Minas Gerais. The following data were collected: anthropometric measurements, blood pressure, percentage of body fat according to dual energy X-ray absorptiometry, and levels of fasting glucose, fasting insulin, triglycerides, total cholesterol, high-density lipoprotein, and low-density lipoprotein. The anthropometric measurements were used for calculating indices and assessing nutritional status. The receiver operating characteristic curve tested whether neck circumference could predict cardiovascular risk. We also investigated how neck circumference related to the study parameters. The significance level was set at 5% (p<0.05). RESULTS: A total of 260 adolescents were assessed of which 50.4% (n=131) were females, 20.4% (n=53) had excess body weight according to the body mass index-for-age index, and 42.7% (n=111) had excess body fat. Blood pressure (3.9%, n=10) and all biochemical parameters were affected, varying from 1.9% (n=5) for glucose to 65% (n=169) for total cholesterol. Neck circumference correlated with body fat, waist circumference, hip circumference, weight, height, body mass index, waist-to-height ratio, homeostasis model of assessment - insulin resistance, fasting insulin, blood pressure, and high-density lipoprotein (<0.05). It predicted excess body fat and changes in fasting insulin and blood pressure in both sexes, blood glucose and high-density lipoprotein in females, and triglycerides in males (area under the curve >0.5; p<0.05, varying from 0.610 for high-density lipoprotein to 0.817 for blood pressure). CONCLUSION: Neck circumference was capable of predicting excess fat and cardiovascular risk factors in adolescents.