Age- and sex-specific annual health-care expenditures (total, in-patient, ambulatory care, and outpatient prescription drug) were estimated within established weight classifications in a nationally representative sample of children and adults aged 6-85 years (n = 80,516) in the Medical Expenditures Panel Survey (MEPS). The expenditures were estimated with two-part regression models and standard errors accounted for the complex survey design. Compared to their normal-weight counterparts, total expenditures were higher for overweight females between age 22 ($85; 95% CI: $1, $166) and age 77 ($623; 95% CI: $14, $1,259); overweight males between age 48 ($168; 95% CI: $9, $312) and age 67 ($612; 95%: $31, $1,139); obese females between age 21 ($88; 95% CI: $12, $207) and age 82 ($1,497; 95% CI: $212, $2,592); and obese males between age 25 ($88; 95% CI: $9, $158) and age 83 ($3,236; 95% CI: $378, $6,637). Differences were primarily due to higher ambulatory care and prescription drug expenditures and, for women only, higher in-patient expenditures. Overweight- and obesity-associated health-care expenditures are substantial and emerge at younger ages for women than for men. Expenditures associated with obesity exceed those associated with overweight. Further research is required to elucidate factors underlying the differences by sex.