School administrators in many schools are steadily reducing physical education time in response to rising pressure to obtain higher test scores in core subjects. This reduction is occurring without a systematic investigation of the contribution of physical education to test scores. The purpose of this quantitative study was to evaluate the relative contribution of socioeconomic status, ethnicity, and weekly hours of physical education to the academic achievement of Mississippi students in third and fourth grade. The study was archival, with an ex post facto design. Aggregated data were used from 109 public elementary schools spread throughout the state of Mississippi, representing 30 school districts and 13 counties. Data were based on student records on file with the Mississippi Department of Education (DOE) for the 2008-2009 school year. The outcomes were computed as the percentages of students in each school with English language arts (ELA) and mathematics test scores reported as either minimum or basic. The percentage of students scoring minimum or basic in ELA was strongly correlated with the percentage of non-White students, r(107) = 0.63, p < 0.001, and with the percentage of students with low SES, r(107) = 0.33, p < 0.001. The percentage of students scoring minimum or basic in mathematics was also strongly correlated with the percentage of non-White students, r(107) = 0.51, p < 0.001, and with the percentage of students with low SES, r(107) = 0.27, p = 0.005. Correlations with physical education hours per week were not significant. Neither the percentage of students of low SES nor the hours of physical education per week predicted test score outcomes after accounting for the percentage of non-White students. The data supported findings of previous research showing ethnicity as a significant predictor of academic achievement. Although less significant, the data from this study also showed low SES as a predictor of academic achievement, and increased physical education time did not improve or hinder performance. While physical education hours were not positively associated with test scores, they also did not detract from test scores. Therefore, educators need to account for the benefits of physical education without concern that these hours will interfere with achievement test scores. [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://www.proquest.com/en-US/products/dissertations/individuals.shtml.]