Adolescents across the United States, in general, do not get enough sleep. This is often the result of early school start times. When children reach adolescence, a biological change occurs, causing their circadian cycle to delay and resisting the build-up of homeostatic pressure. Consequently, adolescents have difficulties falling asleep earlier in the evening. To combat this issue, the American Academy of Pediatrics (2014) recommended middle and high schools not begin their school days before 8:30 am. However, the Centers for Disease Control and Prevention (2015b) found that five out of six middle and high schools in the United States begin their school days before 8:30 am. When students do not get enough sleep, due to early school start times, a buildup of sleep debt occurs, leading to sleep deprivation, affecting daytime functioning and, ultimately, academic performance. However, research has revealed minimal empirical data regarding the relationship between sleep and academic performance. Using the results from the Virginia Standards of Learning Tests from the 2018-2019 school year, the current study aimed to reveal the predictive relationship between school day start time and standardized test results. Ex post facto data were utilized to conduct multiple regression analyses. While mathematics results were statistically significant, reading results were not. Regardless, an hour of delay in daily school start times could result in an increase in reading scores by 2.3% and mathematics scores by 4.8%. This investigation advances the study of the relationship between school day start time and standardized test results, uncovering the underlying relationship between academic performance and adolescent sleep, ultimately allowing adolescents to sleep long enough at night and be as successful as possible during the day. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]