Inadequate sleep among adolescents has negative consequences for self-regulation, emotional well-being, and risk behaviors. Using multiple assessment methods, we evaluated the adequacy of sleep among healthy adolescents from a lower socioeconomic community and expected differences by race. A total of 250 healthy high school students enrolled in public school (mean age: 15.7 years; 57% black, 54% female) from families of low to middle class according to the Hollingshead scale participated in weeklong assessments of sleep duration and fragmentation, assessed by using actigraphy; sleep duration and perceived quality, assessed by using daily diaries; and daytime sleepiness and sleep delay, assessed by using a questionnaire. Students slept during the school week a mean ± SD of 6.0 ± 0.9 hours per night according to actigraphy and 6.8 ± 1.1 hours according to daily diary, and during the weekend, a mean of 7.4 ± 1.2 and 8.7 ± 1.4 hours, respectively. Black participants and male participants slept less and had more fragmented sleep; female participants reported poorer quality of sleep in their daily diaries and more daytime sleepiness. The results remained significant after adjustments for age, physical activity, smoking status, and percentile BMI. Most students slept less than the 8 to 9 hours suggested by the guidelines of the Centers for Disease Control and Prevention. Black male participants had the least amount of sleep, which may play a role in the substantial risks experienced by this demographic group. Our findings are consistent with recommendations that pediatricians should routinely screen their adolescent patients about their sleep, especially those from at-risk subgroups.