Abstract Introduction We are testing strategies to make fall asleep times earlier to extend sleep duration of sleep-deprived, delayed adolescents. We explored whether perceived sleep need was associated with the acceptability of an intervention which included earlier bedtimes on school nights and early morning bright light (BL) on one weekend. Methods Twenty-three participants (16.0±0.7 years; N=11 female) from the intervention group of a study of adolescents reporting ≤7 h sleep on school nights and late bedtimes (school-night≥23:00; non-school night≥midnight) were included. Participants estimated nightly sleep need during baseline. The intervention included shifting school-night bedtimes 1h earlier than each participant’s usual school night bedtime during the first week and 2h earlier than baseline during the second week. Evening time management goals were used to help participants get to bed earlier. Wake times remained stable because of early school start times. During the weekend in between these 2 weeks, participants lived in the laboratory and received very early morning BL on Saturday and Sunday from two light boxes (~6000 lux; three 50-minute exposures with 10-minute breaks). At the end of the study, an acceptability questionnaire asked about hypothetically engaging in different elements of the intervention (earlier bedtimes, morning BL) at home. Items were summed to create a composite acceptability score. Results Participants reported needing 7.8 h (SD=1.2; range=5-9.5h) of sleep. A linear regression demonstrated that needing more sleep was associated with less acceptability when controlling for age and sex, b=1.37, SEb=.60, p=.03. Conclusion Adolescents who felt they needed less sleep were more accepting of an intervention that required earlier bedtimes on school nights and waking up very early to receive BL on the weekend. Interventions that produce less weekend sleep deprivation, like including naps, might be more acceptable to all. Support R01HL105395 (S.J.C.)