While earning a high school diploma is a critical educational milestone for students, research has shown that obtaining a college degree further equalizes opportunities and increases their upward mobility. To be eligible to apply for the University of California system, students must take 15 college-preparatory courses during their high school career. Because students' success is contingent upon passing their courses with a grade of C or better, and research has found instructional time can affect students' academic outcomes, schools must consider how they can best utilize their scheduling to optimize the available time during each class period. While previous studies have shown inconsistent results regarding the effectiveness of school scheduling on student achievement, they are limited because they often draw upon schools from multiple districts or across different states. This study explored the outcomes of 15,482 students across four scheduling types from 12 high schools in the same district. For each of the four scheduling types, three groups of schools were studied. The first group followed a traditional 6-period schedule, the second followed a 7-period schedule, the third followed a 4x4 schedule, and the last group followed a 2x8. The study's results indicated that a 6-period schedule produced better outcomes for GPA, math scores, and UC eligibility, and a 4x4 schedule resulted in more students being on track to graduate. However, when analyzing the data by subgroups, the results were mixed. Additionally, the difference between a 6-period and 4x4 schedule was slight in many cases. The 7-period and 2x8 schedules were the least effective. Based on these results, recommendations emerged regarding district policies and school practices. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]