As four-day school weeks continue to gain popularity among school districts across the United States, determining the potential impact associated with the unconventional school week has become increasingly important (Johnson, 2013). The four-day school week has been credited with producing a number of potential benefits and consequences, but there is currently a limited amount of research available to determine the overall worth of the practice compared to the five-day school week. Some purported impacts of the four-day school week include shifts in teacher and student attendance, changes in achievement, financial adjustments, decreases in dropout rates, and improvement in morale (Plucker, Cierniak, & Chamberlin, 2012). This study involved investigating the system-wide impact of the four-day school week by examining attendance, ACT scores, and dropout rates before and after implementation in participating school districts across Missouri. Additionally, the school climate perceptions of Missouri administrators and teachers who work within the four-day school week were collected. Interview responses were then analyzed using coding methods to identify common phrases, key words, and themes, while the quantitative data were treated to examine pre- and post-implementation patterns. The findings of this study revealed the four-day school week produced a statistically positive significant impact on attendance, whereas ACT scores and dropout rates were not influenced. Furthermore, the perceptions of administrators and teachers indicated the four-day school week was beneficial to the school culture. [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.]