The purpose of this study was to investigate the impact of the demographic characteristics of middle school students on their mathematics performance on the STAAR examination. More specifically, this study examined the effect of the variables gender, ethnicity, and at-risk status, separate and collectively, on the four mathematics components (numerical representation and relationships, computations and algebraic, geometry and measurement and data analysis and personal financial literacy) of the STAAR's examination among middle school students. Additionally, a 2x2x3 factorial design was used in the students. Two hundred forty (240) eighth-grade students enrolled in middle schools in the southern region of the United States. The data analysis for this study was accomplished through the application of the Three-Way Analysis of Variance and the Scheffe Multiple Comparison Statistical techniques. All four hypotheses were tested at the 0.05 level. From the results, this study concludes that eighth-grade students who did not receive a free lunch possessed significantly higher mathematics scores in all sections of the STAAR's examination than those eighth-grade students who received a free lunch. Female middle school students performed academically better than their male peers on the geometry, measurement and computations, and algebraic sections of the STAAR's examination. Male, and female middle school students scored similarly on the numerical representation and relationship section as well as the data analysis and performed financial literacy section on the STAAR's examination. High-income students tend to do significantly better in mathematics on the state's standardized examination than low-income students. [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.]