Better screening tools for paediatric NAFLD are needed. We tested the hypothesis that the postprandial triglyceride (TG) and fibroblast growth factor 19 (FGF19) response to an abbreviated fat tolerance test (AFTT) could differentiate adolescents with NAFLD from peers with obesity and normal weight. Fifteen controls with normal weight (NW), 13 controls with obesity (OB) and 9 patients with NAFLD completed an AFTT. Following an overnight fast, participants consumed a high-fat meal. TG and FGF19 were measured at baseline and 4h post-meal. Liver steatosis and fibrosis were measured via Fibroscan. Fasting TG and FGF19 did not differ among groups; 4h TG in the NAFLD and OB groups were greater (197 ± 69 mg/dL; 157 ± 72 mg/dL, respectively) than NW (105 ± 45 mg/dL; p < 0.05) and did not differ from one another. Within the entire cohort, 4h TG were stratified by high and low steatosis. Adolescents with high steatosis had 98% greater 4h TG than adolescents with low steatosis. 4h FGF19, but not fasting FGF19, was higher in children with low steatosis compared with high steatosis (p < 0.05). Using area under the receiver operating curve (AUROC), the only biochemical outcome with diagnostic accuracy for NAFLD was 4h TG (0.77 [95% CI: 0.60-0.94; p=0.02]). The postprandial TG response is increased in adolescents with obesity with hepatic steatosis, with or without NAFLD. Our preliminary analysis demonstrates 4h TG differentiate patients with NAFLD from those without, supporting a role for the AFTT as a screening tool for paediatric NAFLD.