This study was designed to investigate if a statistically significant variance exists in African American and Hispanic students' attendance and Texas Assessment of Knowledge and Skills test scores in mathematics before and after the implementation of a standardized dress code. For almost two decades supporters and opponents of public school uniforms have debated their effectiveness by conducting studies that measure school administrator, teacher, and parent perceptions; however, only a small number of these studies have focused on student achievement after the implementation process of standardized dress. The purpose of this study was to help broaden the data on the effectiveness of standardized dress codes by focusing on a racially diverse sample of students and their attendance and achievement scores. Previous studies have focused on outcomes such as school safety, staff perceptions of student behavior, and student satisfaction toward the wearing of standardized dress. Data were evaluated by using the Statistical Analysis System (SAS) software, version 9.3, to run parametric two-sample t-tests and a non-parametric Wilcoxon Rank-Sum test. The results of this study suggest the careful consideration of standardized dress code initiatives by school officials, and data should help administrators, school boards, and communities consider the potential implementation of a standardized dress code in a public school district. [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.]