A purpose of this study was to explore the inter-relations among eighth grade mathematics student achievements in the content domains of "Number, Algebra, Geometry, and Data & Chance" and the cognitive domains of "Knowing, Applying, and Reasoning," in the context of the Trends in International Mathematics and Science Study (TIMSS), 2007. A second purpose was to find the associations between student achievements in the cognitive domains with student-related, teacher-related, school-related, and home-related variables. The variables were selected mainly on the basis of Carroll's model of school learning. Further, the math achievement of the students of the United States in each of the domains was compared with "Bulgaria," "Chinese Taipei," "Republic of Korea," "Singapore," and "Thailand." After analysis, interpretations were made on the findings of the relationships among student achievements in each of the content and cognitive domains and also on the associations between variables and math achievement in the four content domains. Further, comparative performance of the U.S. with each of the five selected countries in each of the seven domains was analyzed. For finding the relationships among student performance scores across all the countries in eighth grade mathematics in different domains, Pearson's product moment coefficient of correlation was used as the measure. For finding the associations of the scores with the variables, multiple regression method was employed. Finally, for comparing student performances of the U.S. with other states, independent samples t-test was used. The findings of this study indicated that student performance in all the content and cognitive domains were highly correlated. The second finding was that the variable "School Resources" was significantly related to student performance in each of the content domains, whereas "Overall Home Involvement" had moderately significant relation with student achievement in "Number" and "Data & Chance." The findings revealed no significant relation between the other variables considered and student achievement in the four content domains. The third finding showed that "Chinese Taipei," "Republic of Korea," and "Singapore" outperformed the U.S. in all the domains, whereas the U.S. performed better than "Bulgaria" and "Thailand" in each of the domains. These results provide some clues for improving classroom instruction and streamlining administrative priorities in order to improve student performance in the United States. Furthermore, the results indicate paths for further research in order to augment the educational practice not only in the U.S., but in all countries, for securing better student achievement in mathematics. [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.]