Background/Purpose: Despite the importance of sleep for athletic performance, there is a lack of normative sleep data and sex comparisons in collegiate athletes. The primary purpose of our study was to assess the prevalence of insufficient sleep in collegiate athletes, with a secondary aim to compare male and female athletes. Procedures: Participants included 121 collegiate athletes (65 men and 56 women) from six team sports and three individual sports. Subjective assessments of sleep included at-home sleep diary, Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS), and Insomnia Severity Index (ISI). Objective assessments of sleep included three consecutive off-season weekdays of wrist actigraphy to assess total sleep time (TST) and sleep efficiency (SE). Main Findings: Actigraphy revealed that 94% of student-athletes received <8 hours of sleep/night, while 61% received 7 hours/night. Subjective assessments revealed that 35% had PSQI 5, 28% had ISI scores >7, and 19% had ESS scores >10. Objective TST was not different between sexes (6.70.1 vs. 6.70.1 hours, P = .99), but females demonstrated higher SE (87 +/- 1 vs. 82 +/- 1%, P < .01) and lower WASO (31 +/- 2 vs. 38 +/- 2 min, P = .02). Male athletes significantly overestimated TST (i.e., subjective minus objective TST) when compared to female athletes (Delta 0.7 +/- 0.1 vs. Delta 0.3 +/- 0.1 hours/night; P < .01). PSQI, ISI, and ESS were not different between sexes. Conclusions: The majority of male and female collegiate athletes received less than age-recommended levels of sleep, and 44% subjectively reported poor sleep quality, mild severity insomnia, and/or excessive daytime sleepiness. Sex differences were observed in male and female collegiate athletes. (C) 2020 National Sleep Foundation. Published by Elsevier Inc. All rights reserved.