The study's purpose was to examine large and small high schools in Virginia to try to understand if the high school student population size influenced the student achievement of eleventh grade students based on identified predictor variables. Several studies were identified and included in the literature review. From the literature review, the predictor variables of socioeconomic status, student attendance, minority status, and teacher quality were identified to aid in the development of the main research question and five guiding questions. The main research question investigated if there was a relationship between a high school student population size and student achievement when statistically controlling for selected predictor variables. From the literature review, the main research question, five guiding questions, and a methodology were developed that would best aid in the analysis of the data. Data were collected from the Virginia Department of Education for the 2012-2013 school year that consisted of eleventh grade Virginia Standards of Learning assessments, socioeconomic status, student attendance, minority population, and teacher quality. Hierarchical multiple regression was the statistical method used to analyze the data for the research questions. The results of the study indicate there is a relationship between socioeconomic status and student achievement. However, when student population size was introduced, the result was not significant. The overall conclusion regarding socioeconomic status and student achievement is that the issue is not rooted in the size of a high school population. When student attendance was accounted for, a relationship existed between high school student population size and student achievement. When student attendance was accounted for, an indication existed that the high schools in the study with both large and small student populations had a higher percentage of student achievement when students attended on a regular basis. When the size of a high school student population, whether it was large or small, was taken into account, student achievement declined if a high school had a large percentage of minority students. Teacher quality was found to have a relationship with student achievement when high school student population size was taken into account. Overall, results of the study indicate that there was a relationship between a high school student population size and student achievement when statistically controlling for isolated variables. / Ed. D.