Background: Although adolescence and obesity are related to impaired sleep duration and quality, exercise was admitted as a nonpharmacological treatment for sleep and better control of energy balance.Objectives: To investigate the acute effects of intense exercise on sleep and subsequent dietary intake.Methods: Sixteen adolescent girls with obesity (age 13.7 ± 1.1 years, weight 82.7 ± 10.2 kg, body mass index (BMI) 30.5 ± 3.4 kg/m 2 , fat mass (FM) 39.2 ± 3.1%, Pittsburgh Sleep Quality Index (PSQI) 8.6 ± 2.8, paediatric daytime sleepiness scale (PDSS) 19.6 ± 5.9) took part in two experimental sessions in a random order: Control (CTL) and Exercise (EX). The two sessions were identical except for a continuous ergocycle exercise bout lasting 40 minutes and performed at 70% VO 2max at the end of the morning of EX. Energy expenditure and sleep were measured by accelerometry and next-morning dietary intake in an ad libitum meal.Results: Higher sleep duration (P < 0.03) and quality (decreased WASO: P < 0.02; increased SE%: P < 0.02) were observed in EX compared with CTL. This was associated with a nonsignificant decrease in caloric intake (−78 kcal) and a significant decrease in food energy density (P < 0.04), fat, and sugar consumption (respectively, P < 0.02 and P < 0.05) the following morning.Conclusions: Acute exercise efficaciously increased sleep duration and quality, resulting in a decrease in subsequent energy-dense food consumption in adolescent girls with obesity. K E Y W O R D S accelerometry, dietary behaviour, girls with obesity, physical activity, sleep