The lack of formal grading policies within individual schools and school districts results in differential grading across classrooms. In many secondary schools, an individual course may be taught by multiple teachers. This study aimed to determine if the existence of differential grading results in disparate outcomes for students based on their assigned teacher. Data about students (demographics, teacher-issued grades, and standardized test scores) was collected from four core content classes at one high school. Regression analysis was used to isolate the impact of students' assigned teacher on their course grade after controlling for demographics and academic performance as measured by the standardized test associated with each subject. The findings showed that the "teacher" factor was significant for all four courses. Given the importance of grades to students' academic trajectories, these findings should be of concern to all stakeholders, from students and parents to classroom teachers and school administrators. [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.]