CONTEXT: Studies have associated obesity with peripubertal hyperandrogenemia. However, these studies were performed in academic centers and could have been influenced by selection bias. OBJECTIVE: To investigate if free testosterone levels are elevated in peripubertal girls with obesity. DESIGN/SETTING: We analyzed data from the National Health and Nutrition Examination Survey 2013-2016 databases. PARTICIPANTS: 1299 girls aged 6-18 years residing in the United States. MAIN OUTCOME MEASURES: Mean free testosterone concentration (calculated from total testosterone and SHBG). RESULTS: Among girls aged 6 to 9 years, mean (95% confidence interval) free testosterone was 0.33 pg/mL (0.28-0.38) in healthy-weight girls vs 0.86 pg/mL (0.67-1.05) in girls with obesity. Among girls aged 10 to 14 years, free testosterone was 2.29 pg/mL (2.05-2.53) in healthy-weight girls vs 4.10 pg/mL (3.60-4.60) in girls with obesity. Among girls aged 15 to 18 years, free testosterone was 3.33 pg/mL (2.96-3.70) in healthy-weight girls and 5.64 pg/mL (4.93-6.36) in girls with obesity. Girls with obesity in all age groups had higher free testosterone levels compared to healthy-weight girls. In each age group, the 95% confidence intervals for free testosterone did not overlap between healthy weight vs obesity subgroups. A multiple regression model accounted for 42% of the variance in free testosterone (R2 = 0.42), and both weight and age categories were independent predictors of free testosterone (P <
.0002 for each). CONCLUSION: In a nationally representative sample of US girls, obesity is associated with elevated free testosterone, suggesting an important relationship between obesity and peripubertal hyperandrogenemia.