This study examined the impact that a year-round school calendar and a traditional school calendar may have on student achievement at selected elementary schools in North Central South Carolina. Specifically it investigated mean differences in academic achievement between elementary students at two year-round schools versus two traditional calendar schools using the Palmetto Achievement Challenge Test (PACT) data of fourth grade students in English Language Arts and Mathematics for the academic school year 2006-2007. This study further investigated academic achievement subgroups by gender, social ethnicity, and socio economic status students. A total of 256 elementary students were included in the study. 48% of students were enrolled at year-round schools and 52% of the elementary students were at traditional schools. Descriptive statistics was used to summarize the data for this study and Analysis Covariance was used to examine for mean differences as well as control for students' prior academic knowledge. The results found in comparison to year-round versus traditional school calendar in North Central South Carolina, no significant statistically differences in student achievement in English Language Arts and Mathematics. Adjusting the school calendar did not significantly advance academic achievement nor did the findings indicate significant increases in achievement by subgroups. [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.]