Study Objectives: To examine bi-directional, temporal associations between daily sleep and affect under naturally constrained (school) and unconstrained (vacation) sleep opportunities, while simultaneously incorporating both valence (positive versus negative) and arousal (high versus low) dimensions of affect. Methods: Sleep and affect were measured over 2 weeks of school and 2 weeks of vacation in 205 adolescents (54.1% females, Mage=16.9 years), providing 5231 days of data. Total sleep time (TST) and sleep efficiency were measured using actigraphy and sleep diary. High- and low-arousal positive and negative affect (PA, NA) were self-reported each afternoon. Between- and within-person sleep-affect associations were tested using cross-lagged, multilevel models. Lagged outcome, day of the week, study day, and sociodemographics were controlled.Results: Bi-directional associations between self-report sleep and affect were found on the between-person level: longer self-report TST associated with lower high and low arousal NA. Higher high arousal PA associated with longer actigraphy TST between-persons, but predicted shorter same-night actigraphy TST within-persons. Results did not differ between school and vacation. Significant within-person random effects demonstrate individual differences in daily sleep-affect associations. Conclusions: Associations differed based on sleep measurement and affect dimensions, highlighting the complex relationship between sleep and affect. Strong between-person associations between self-report sleep and affect suggest that improving either sleep or mood may benefit the other. Although overall high arousal PA was protective of sleep duration, on a day-to-day basis, higher-than-usual high arousal PA may reduce sleep duration on nights it is experienced. Further research needs to identify causes of individual differences in sleep-affect associations.