The sixth grade is very important for education stakeholders, as it marks the beginning of the transition period for students to high school. No consensus has been reached so far among scholars on whether block scheduling is the best way to provide students the time that is necessary to facilitate effective learning and the retention of knowledge. The purpose of this quasi causal-comparative, ex-post facto study was to determine the effectiveness of block scheduling in improving the mathematical performance of sixth-grade students by using data from a selective Nebraska public school system regarding the performance of its sixth-grade students on their state assessment evaluation scores in traditional and nontraditional schedules. The researcher analyzed the results of a mathematics assessment from one school in the Nebraska public school system, using data from learners at the sixth-grade level as the specific purposeful sample. The results indicated that there were no significant differences found in student mathematical proficiency scores for each type of scheduling. This suggests that the type of scheduling of mathematics courses does not influence a student's mathematical achievement. This conclusion also held true when comparing the students of various races, free or reduced lunch status, and genders. Due to limitations including missing data and an intermittent block schedule, the researcher cannot conclude that block scheduling improves academic performance; further studies are recommended. [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.]