Context: Pediatric obesity is common, particularly in children treated with antipsychotic medications. Antipsychotic exposure can increase cardiometabolic risk by increasing adiposity, and possibly via other adiposity-independent pathways. Objective: The objectives were to characterize relationships of adiposity with intrahepatic triglyceride (IHTG) content and carotid intima media thickness (CIMT) in children with and without antipsychotic drug treatment, and to explore whether Vitamin D alters any effects in these relationships. Design: This was a cross-sectional case-control study. Setting: The setting was an academic medical center. Patients or Other participants: Participants were 44 children (ages, 6-19 y): 25 cases treated with antipsychotic and other psychotropic drug therapies and 19 untreated controls, frequencymatched on age, gender, and body mass index. Main Outcome Measures: Main outcome measures were dual-energy x-ray absorptiometry percentage body fat (DEXA %fat), IHTG measured by magnetic resonance spectroscopy, and CIMT measured by ultrasonography. Fasting blood glucose, insulin, lipids, C-reactive protein, and liver enzymes were also evaluated. Results: There were no significant differences between cases and controls on measures of IHTG, CIMT, or DEXA %fat. In combined crude and adjusted analyses, DEXA %fat predicted IHTG (R2 = 0.30) but not CIMT. Low levels of Vitamin D were associated with larger effects of DEXA %fat on IHTG. Conclusion: In treated and untreated children alike, adiposity is a significant predictor of liver fat content. This relationship was altered by low Vitamin D level. These results suggest a modifiable pathway to hepatic steatosis. Further research is needed to test the hypothesis that children with high adiposityandlowvitaminDhave particularly increased risks for thedevelopmentof fatty liver.