STUDY OBJECTIVES: This study examined associations between average and intraindividual trajectories of stress, sleep duration, and sleep quality in college students before, during, and after transitioning to online learning due to the COVID-19 pandemic. METHODS: One hundred and sixty-four first-year college students answered twice-weekly questionnaires assessing stress exposure and perception, sleep duration, and sleep quality from January until May, 2020 (N = 4269 unique observations). RESULTS: Multilevel growth modeling revealed that prior to distance learning, student stress was increasing and sleep duration and quality were decreasing. After transitioning online, students' stress exposure and perception trajectories immediately and continuously decreased; sleep quality initially increased but decreased over time; and sleep duration increased but then plateaued for the remainder of the semester. Days with higher stress exposure than typical for that student were associated with lower sleep quality, and both higher stress exposure and perception at the transition were linked with simultaneous lower sleep quality. Specific groups (eg, females) were identified as at-risk for stress and sleep problems. CONCLUSIONS: Although transitioning to remote learning initially alleviated college students' stress and improved sleep, these effects plateaued, and greater exposure to academic, financial, and interpersonal stressors predicted worse sleep quality on both daily and average levels. Environmental stressors may particularly dictate sleep quality during times of transition, but adaptations in learning modalities may help mitigate short-term detrimental health outcomes during global emergencies, even during a developmental period with considerable stress vulnerability. Future studies should examine longer-term implications of these trajectories on mental and physical health.